Unpacking the complexity of the UK plastic packaging value chain: A stakeholder perspective

The pace to achieving a sustainable plastics economy remains noticeably slow due to a lack of understanding on the role and importance of stakeholder dynamics in the plastic packaging system. This study aims to unpack and assess the role of stakeholders in improving plastics recycling rates and circularity in the UK, using polyethylene terephthalate (PET) drinks bottles value chain as a case study. Via the theoretical lens of stakeholder theory we identify and group the stakeholders involved in the PET dinks bottles value chain, and integrate this in the Complex Value Optimisation for Resource Recovery (CVORR) systems thinking approach to make sense of, and analyse, stakeholders complex interactions. Results highlight that even though, external stakeholders (e.g. NGOs, trade associations) engage on different levels and scales in promoting circularity in the PET bottles value chain, there is strong drive in incentivising production and consumption processes driven by the significant lobbying power of internal stakeholders operating upstream of the PET bottles value chain (i.e. producers and brand owners). This lobbying power, which arises from the well-established market of PET bottles in the UK, and its support by financial institutions, it strongly influences national and local government policies and decision-making processes. Meanwhile, the waste management processes are short-sighted, being unable to gain improved momentum and increasing the PET bottles recycling rates. This dynamic conceals, and somewhat retains, the prevailing resistance in removing the infrastructural, regulatory and technological lock-ins. The development of an interdisciplinary collaboration between internal and external stakeholders is paramount to sustainably managing PET drinks bottles in the UK and achieving a transition to a sustainable circular plastics economy. Fostering closer collaboration between all stakeholders involved in the system, can aid the development of new value networks and support new policy interventions that can improve circularity in the plastic packaging sector. Drawing on stakeholder theory we classify (internal vs external) and group (according to their roles) stakeholders involved in the PET drinks bottles system in the UK, and map them along the value chain, differentiating between upstream (design, production and consumption) and downstream (disposal, collection, sorting and mechanical reprocessing) processes. We then examined the power relationships of these stakeholder groups by employing the CVORR approach and synthesising evidence on their roles and interactions on promoting sustainability in the plastics packaging system. This integrated approach is supported by a narrative literature review on the role of stakeholders in increasing the sustainability of the UK plastic packaging value chain.


Introduction
The increasing production and consumption of plastics used in the food packaging sector, and the subsequent plastic packaging waste generation and mismanagement have raised global concerns and highlighted the need to take measures to reduce, remediate and prevent plastic waste and pollution (Iacovidou et al., 2020). In response, there has been a series of plastic industry efforts and government interventions, to boost plastics circularity, and decrease their impact on the environment (Iacovidou et al., 2020, Evans et al., 2020. The European Union (EU), following the first Circular Economy Directive (EC, 2015), has set ambitious goals to boost plastics circularity. In the UK, there is now a set of strategic plans, frameworks and actions published by the UK government that aim to tackle and address plastic waste and pollution, such as the 25 Year Environment Plan (HM Government, 2018a), the Resources and Waste Strategy (HM Government, 2018b), and the UK Plastics Pact (WRAP, 2018). Yet, the pace of change remains alarmingly slow, and solutions promoted or implemented regionally and globally are highly fragmented and mostly insufficient, whilst they may create lock-ins (Crippa et al., 2019). A holistic understanding of the dynamics involved in the plastic packaging system is needed to seize the multi-dimensional benefits of transitioning to a sustainable circular plastics economy. At present, there is little research that has directly addressed this objective (Iacovidou et al., 2020).
Studies have hitherto concentrated on assessing the function and end-of-life (EoL) fate of plastic food packaging (Geyer et al., 2017, Luijsterburg and Goossens, 2014, Hahladakis and Iacovidou, 2018, Narancic et al., 2018 and focused explicitly on assessing the life cycle environmental and human health impacts of plastics production, use and management (Groh et al., 2019, Williams and Wikström, 2011, Velis and Cook, 2021, Karbalaei et al., 2018, rarely expanding on economic and social impacts (Hahladakis and Iacovidou, 2019, Iacovidou et al., 2020, Su et al., 2020. A small number of studies focused on the social dimensions and role of media in reducing plastic waste and pollution (Rhein andSchmid, 2020, Compagno, 2020), or on chemical additives used in fine-tuning the properties of plastic packaging and their impacts on the terrestrial and marine environment (Bradney et al., 2019, Hermabessiere et al., 2017, Hahladakis et al., 2018b. Most recently, studies have also documented the generation and impact of micro-and nano-plastics for the global environment and society (Karbalaei et al., 2018, Chang et al., 2020, Hu et al., 2019. Other studies have delved into exploring the introduction of alternative materials, so-called bioplastics, and their lifecycle impacts (Gerassimidou et al., 2021, Bishop et al., 2021, Escobar and Britz, 2021. Whilst the findings of the above research are unquestionably important, the chain of processes and links between all stakeholders involved in the plastic packaging value chain, and their interactions across all stagesfrom production and distribution, to EoL management -need to be closely examined to effectively orchestrate the flows of complex value across the plastic packaging system. Complex value, refers to the measurable benefits (positive value) and impacts (negative value) in the environmental, economic, social and technical domains as influenced by the political dimensions (e.g., political discourse, policy instruments, policymaking) (Iacovidou et al., 2017). In a recent report, we highlighted that an effective communication among stakeholders, and coordination of their actions, is necessary to achieve sustainability in the plastic packaging management system, following a high-level generic stakeholder analysis (Iacovidou et al., 2020).
Considering the importance of understanding the chain of processes (i.e. value chain activities and performance) and structures (formal / informal networks of actors) created and shaped by the relations between stakeholders in a system, the types and roles of stakeholders involved in the entire plastic food packaging system need to be explored (Iacovidou et al., 2020). Stakeholders here refer to any group or individual involved in the value chain, who has an interest, and can affect or is affected by the plastic food packaging value chain, after Freeman (2010; see also first ed. 1984) and Friedman and Miles (2006). From that perspective, the conceptual analysis of the power relationships among stakeholders involved in the plastic food packaging system, and evaluation of the multifaceted processes evolved via their relations at regional level, play an important role in understanding and addressing the plastic waste and pollution problem (Fazey et al., 2014, Weichselgartner andKasperson, 2010). Power relationship refers to the exchanges / interactions between two or more stakeholders, indicating the extent to which one stakeholder is able to cause other stakeholders to engage in activities that would not be taken otherwise (Tang and Tang, 2012). Dynamics refer to the changing attributes, roles, perceptions and intentions of stakeholders involved in the system (de Blois and De Coninck, 2008) leading to cause and effect relationships that evolve and change over time (Iacovidou et al., 2020). Dynamics and power relationships are intertwined, and we will refer to power dynamics.
In the plastic food packaging system, spatial and temporal granularity per plastic type is necessary for unravelling the power dynamics involved in the complex plastic packaging value chain (Iacovidou et al., 2020). This is because the production, use/consumption and management of different types of plastic packaging is determined by the properties and application of each polymer type, as well as several factors related, but not limited to, stakeholder heterogeneity (Mercure et al., 2016); interconnectivity (i.e. a large and an increasing number of relationships between stakeholders (Grösser, 2017); high-level nonlinearity (i.e. unpredictable effects from different stakeholder networks (Thomas et al., 2016); and spatial-temporal variations (i.e. correlation between commodity, business and geographical-temporal conditions arising from overlapping governance structures, administrative boundaries and changes over time (Zhang and Chang, 2021), that mobilise and affect plastic packaging flow in the value chain (New_InnoNet, 2016).
Polyethylene terephthalate (PET) is the most commonly used plastic packaging for the containment of beverages, e.g. carbonated drinks, still drinks, fruit juices and bottled water, and accounts for 70% in the total soft drink production (BPF, 2021b). The widespread prevalence of PET bottles in the beverage sector arises from a range of favourable properties such as flexible, hygienic, strong, lightweight, shatterproof, and freshness retention (BPF, 2021b). PET drinks bottles is one of the cleanest plastic waste streams, making PET drinks bottles one of the most widely collected plastic packaging material for recycling globally. Even though the levels of collection and recycling of PET drinks bottles vary widely from one region to another, there is a general preference for diverting PET bottles from landfill, incineration with energy recovery, and mechanical biological treatment (MBT) processes to recycling. In the UK specifically, in 2017, the recycling rate of PET drink bottles was estimated around 67% (Valpak, 2017), while the recycling rate of total plastic packaging did not exceed 47% (DEFRA, 2020).
Using the PET drinks bottles value chain in the UK, the study seeks to explore the impact of the power dynamics of stakeholders involved in the plastics value chain on achieving a sustainable plastics economy. It addresses an important research gap that has remained largely underexplored.
Specifically, the study aims to explore who are the main stakeholders involved in the PET bottles system and their respective roles in the system, and how the power dynamics between them impact on the ability of PET bottles to circulate back in the system. Whilst, PET drinks bottles are amongst the top ten littering items in the UK (UKMMAS, 2015), and a portion of it may still end up in the residual waste bin, and subsequently, in landfills, incineration, or MBT facilities, these points of 'complex value loss' are considered to be outside the scope of the present study. Here, our focus is on the management of PET bottles via recycling (as in mechanical reprocessing), and our analysis consists of the following tasks: i) providing a preliminary conceptualisation of all stakeholders involved in the upstream and downstream part of the value chain of PET bottles in the UK (Section 4.1); and ii) grouping stakeholders according to their role and map them across the PET bottles recycling value chain (Section 4.2); iii) examine how power dynamics between stakeholders are driving and shaping activities within the PET bottles system with a focus on recycling (Section 4.3). Two theoretical frameworks were combined to unpack the complexity of the PET drinks bottles value chain that are fully described in Section 2: i) stakeholder theory, a stand-alone framework that is widely used in social sciences for the identification of stakeholders (Freeman, 2010); and ii) the Complex Value Optimisation for Resource Recovery (CVORR), a newly developed stand-alone approach that combines multi-disciplinary theories and tools to holistically assess a system (Iacovidou et al., 2020). This novel, integrated approach can unveil the dynamics and other multifarious aspects that enable and/or hamper the recycling of PET drinks bottles, and in turn, generate insights for future research and guide circularity interventions. This work supports a better understanding of how the various policy interventions, current and planned, need to be coordinated to deliver the desired outcomes.

Regulatory framework of PET bottles management in the UK
The purpose of this section is to present the current legislative framework on the management of plastic packaging waste and PET bottles specifically. This section underpins the critical role of authorities in achieving the targets and objectives set. The European Strategy for plastics in a Circular Economy (EC, 2018a) entails that, by 2030, all plastic items shall be reusable and recyclable, and that recovery, sorting and recycling technologies shall be developed and introduced, including food-grade recycled plastic packaging. The Directive 852/2018 on packaging and packaging waste, mandates that 50% of plastic packaging waste shall be recycled by 2025, and 55% of plastic packaging shall be recycled by 2030 (Directive 2018(Directive /852, 2018. According to Directive 904/2019, from 2025 PET bottles placed on the market shall contain at least 25% of recycled plastic, and, from 2030 PET bottles shall contain at least 30% of recycled plastic (Dirctive 2019/904, 2018). Considering the increase in plastic production and consumption, and the challenges confronted in reaching the above targets, the EU released in 2020 the New Circular Economy Action Plan (EC, 2020a). This plan introduces further targeted measures for packaging waste including the restriction of intentionally added microplastics and the development of labelling and certification measures. For this purpose, the EC report "A Circular Economy for Plastics" highlights the current existing limits for plastic waste recovery and recycling, including the pending approval of plastic recycling processes from the European Food Safety Agency (EFSA) (Crippa et al., 2019).
Concurrently, the EU has begun to harmonise, design and complete regulations related to food contact materials. Food contact material Regulation 1935/2004(EC 1935/2004) and Regulation 2023/2006(EC 2023/2006, which was amended by regulation 282/2008 (EC 282/2008), consider aspects of safety, and looked at the traceability of recycled plastic content used in food contact materials, considering related implications for human health, the environment, and products' market. The abovementioned requirements are consolidated in Regulation 10/2011 (EC 10/2011), which defines specific requirements for plastic food contact materials. These regulations merge in a new European strategythe Farm to Fork strategy (EC, 2020b) -that aims, among other aspects, to scrutinise food contact materials legislation to enable and improve the use of sustainable packaging material, including recycled and reusable packaging.
The impact of using recycled content in new plastic food contact materials have been emphatically discussed in many studies (Matthews et al., 2020, Hahladakis and Iacovidou, 2019, Paletta et al., 2019, with authors arguing that the levels of additives present has to be thoroughly explored to mitigate potential consequences on human health and food quality. Regarding this concern, a communication from the European Commission (EC) [COM/2018/032] highlighted that chemical substances should be forbidden when risks are evaluated indicating that products legally produced may contain substances that later may be forbidden and therefore the generated waste may contain forbidden substances (EC, 2018b). These 'legacy substances' constitute a barrier to transitioning in circular economy indicating the need to develop decision making process that support recycling of these wastes considering the financial benefits of recycling against disposal (EC, 2018b).
The UK is now outside the EU and is currently developing new environmental protection strategies and/or upgrade existing transposed EU regulations on waste. Nonetheless, new Food Contact Material regulations and national standards will need to comply with the regulatory requirements of food products traded with the EU (HM Government, 2018b). EU regulations that will be maintained, are: avoidable plastic waste is defined as waste that could have been reused, recycled or composted. The UK government asserted its intention to deviate the market towards reusable and recyclable plastics by strengthening the extended producer responsibility (EPR) for packaging, imposing a tax on plastic packaging produced with less than 30% of recycled plastics, and introducing a deposit return scheme (DRS) for drink containers (Smith, 2021).
In spite of our regional (UK) focus, it is evident from the above that some stakeholders outside these boundaries may affect the production, distribution, use and management of the PET bottles. As such, these stakeholders will be included in our analysis.

Theoretical framework of PET bottles management in the UK
The study makes use of stakeholder theory to identify and group stakeholders into categories according to their interests, priorities and roles (Hörisch et al., 2014). This is then integrated into the CVORR approach, that further maps stakeholders according to their position and roles along the value chain. Drawing on the integrated systems thinking analysis, the study uncovers the power dynamics between stakeholders that act upstream (i.e. stages occurring at the production-consumption) and downstream (i.e. stages occurring at the consumption (disposal)-management) of the PET drinks bottles value chain, and explores their influence in promoting plastics recycling and circularity in the UK.

Stakeholder theory
The stakeholder theory has been gaining increased attention in sustainability and circular economy research, policy and practice , Ihlen and Berntzen, 2007, Lindgreen and Swaen, 2010, Sarkis et al., 2011, due to the ever-increasing importance in underpinning the vast number and role of stakeholders in complex value creation in the resource recovery systems (Freeman et al., 2010, Friedman andMiles, 2006). It has evolved within the management field to understand the way businesses operate and their impact on value creation and sustainability, as well as to inform businesses on ethics, responsibility and accountability in protecting the environment . As a concept it originates from the epistemological foundations of systems theory and corporate social responsibility (Ackoff, 1988, Freeman andMcVea, 2001), which together can aid an improved understanding of the multi-dimensional impacts of stakeholders' activities, and the design of effective strategies and interventions (Porter, 2008). This signifies that stakeholder theory is, in fact, perfectly suited to the identification and understanding of the complex array of stakeholders involved in a system, such as a resource recovery system. Resource recovery refers to the processes wherein waste generated at all stages of production and consumption, either in the form of natural resources or man-made materials, components, products, are recovered and maintained in the system.
According to the stakeholder theory (Freeman, 2010), there are many definitions that emerged over the past years to describe and group stakeholders in a business environment (e.g. industry and commerce); yet the pragmatic approach put forth by Freeman et al. (2010) makes clear that stakeholders can be grouped based on their purpose into: i) those whose interest(s) emerge via their direct involvement (day to day activities) in the business (Harrison, 2003) -or "those groups without whose support, the business would cease to be viable" , and are therefore conceived as parts of a company, commonly referred to as internal stakeholders (Harrison, 2003), or primary stakeholders  . Internal, or else primary, stakeholders include shareholders (or owners) who own a company or part of it through shares of stock and have a financial stake in the business and expect some form of financial return from them; suppliers who provide services or produce raw materials and in return receive part of financial return from products and services; customers or product consumers who purchase the product of the company for personal use and receive the benefit from products and services; and employees who are hired by the company to conduct a specific task under terms of employment and put their livelihoods at stake; and i) those whose interest(s) emerge via their indirect involvement in the business; hence, they are not part of a company but they affect or are affected by its activities, commonly referred to as external stakeholders (Harrison, 2003), or secondary stakeholders . Most common external stakeholders are: financial institutions (Banerjee et al., 2003) ; government (national and local government departments and agencies, and bodies that have a legally recognised regulatory function (ISO, 2019) that give rights to internal stakeholders (e.g. to build facilities) and in turn benefit from the tax base and socio-economic contribution of a business; non-governmental organisations (NGOs) (charitable, not-for-profit or non-profit organisations with a public interest objective related to social or environmental concerns (ISO, 2019) that keep businesses accountable for their responsibilities and accountabilities towards sustainability; consumers advocates, related to the preservation of consumers rights; unions, organisations that negotiate with businesses and usually represent workers (e.g. trade unions); associations that are membership organizations to promote the interests of their members -businesses or entrepreneurs from a specific industry area (Boleat, 1996); competitors indicating the relationship among companies that provide similar goods or services to the same group of consumers; media, communication channels that provide public awareness of the product; and research institutions that provide research services to a specific scientific field.
We distinguish between two types of investors: (a) financial investors who are primarily interested in the financial risk-return aspects of an entity's securities and their portfolio-fit -this group can be subdivided into two subgroups: retail-investors and institutional investors; and (b) strategic investors who are primarily interested in the operational capabilities and goods and services of their investee companies that are relevant for their own production processes. The latter group we refer to as 'shareholders'. Retail-investors are those who buy stocks from traded companies as part of their portfolio and sell to consumers (retailers) or other companies (wholesalers); and institutionalinvestors, such as banks, savings and loan associations and insurance companies, who invest the money of their clients to buy securities or assets (CFI, 2021). In this study, institutional-investors, were included under 'financial institutions'. Thereby, with 'investors' we refer to retail-investors.   (2010). In the following text, we refer to stakeholder categories using the codes in front of categories.
The International Association for Public Participation (IAP2) has developed an internationally recognized model that describes the influence of stakeholders on public decision-making, known as IAP2 spectrum (I2S, 2021b). Specifically, the IAP2 spectrum is used to identify the participation of internal and external stakeholders at different levels of engagement in complex issues and challenges (Salvioni and Almici, 2020), depending on their communication strategy, and time span of the relationships that stakeholders establish with one another (Bammer, 2019). Based on their relationships, stakeholders are able to influence the direction of decision-making, and related processes, which differ according to the type of engagement (Salvioni andAlmici, 2020, Bammer, 2019).
The IAP2 is a useful approach to exploring the engagement of stakeholders in complex research problems (Bammer, 2019). Stakeholder engagement is defined as "the process used by an organisation to engage relevant stakeholders for a clear purpose to achieve agreed outcomes (p.34)" (AccountAbility, 2015). The IAP2 has previously been used to assess stakeholder engagement in transitioning to circular economy at a company level (Salvioni and Almici, 2020). Here, we adopted this spectrum to explore stakeholder engagement in a resource recovery system (i.e. PET drinks bottles) (I2S, 2021b, Bammer, 2019). In Table 1, we illustrate the way IAP2 spectrum was used to indicate the processes used by internal stakeholders to engage external stakeholders, and vice versa, in transitioning towards sustainable resource recovery systems.

Complex Value Optimisation for Resource Recovery (CVORR) approach
CVORR is "a novel systems thinking approach that helps in understanding and reforming natural resources and waste management systems (p.13)" (Iacovidou et al., 2020). It seeks to understand and assess system dynamics, drivers and barriers of sustainable complex value creation across any resource recovery system (Iacovidou et al., 2020). It has been proven a reliable tool to assess the plastic packaging system holistically, and generate insights into the processes and stakeholders interrelationships and their multi-dimensional impacts on resource recovery systems (Iacovidou et al., 2020).
The CVORR tool mobilises that analysis by scrutinising the mass and monetary exchanges and other 'transaction' dynamics (e.g. permits, certificates of compliance with regulations or quality standards etc.) between all stakeholders involved directly and indirectly in the resource recovery system. Within the CVORR tool, a step-wise framework is used to collect and synthesis relevant information within five interacting spheres, called the five levels of information. This framework allows the conceptualisation of complex value (Iacovidou et al., 2020), and further encapsulates the role(s) of relevant stakeholders operating therein. These interacting spheres are as follows: • 1 st level: Natural environment and provisioning services -refers to the natural flows and provisioning services ability to maintain and enhance living systems; • 2 nd level: Technologies, infrastructure and innovation level -refers to infrastructure and innovation level of transforming waste into secondary resource; • 3 rd level: Regulatory framework and political landscape -refers to governance, regulatory framework and political landscape; • 4 th level: Business practices, and the market -refers to the activities performed by businesses and influenced by market forces • 5 th level: User practices -refers to patterns of behaviour related to meeting human needs and values.
The way different stakeholders interact with one another can determine the complexity of the system, and can reveal how their power dynamics influence the sustainability culture, political processes, competition, shared responsibilities, and integration of circular business models in the PET drinks bottles value chain, amongst others. Understanding how the power dynamics between stakeholders affect the (enabling) conditions at each of the five interacting spheres (levels of information), can highlight opportunities and barriers in creating complex value, and develop mechanisms aimed at leveraging stakeholder engagement towards sustainable resource recovery.

Methodology
Drawing on stakeholder theory we classify (internal vs external) and group (according to their roles) stakeholders involved in the PET drinks bottles system in the UK, and map them along the value chain, differentiating between upstream (design, production and consumption) and downstream (disposal, collection, sorting and mechanical reprocessing) processes. We then examined the power relationships of these stakeholder groups by employing the CVORR approach and synthesising evidence on their roles and interactions on promoting sustainability in the plastics packaging system.
This integrated approach is supported by a narrative literature review on the role of stakeholders in increasing the sustainability of the UK plastic packaging value chain.
The search strategy was designed and implemented in two stages as follows: 1) selection and use of keywords in scientific databases, such as Scopus, Web of Science and Google Scholar, to source information related to PET materials, components and products (e.g. "PET", "plastics", "PET bottles", "packaging", "beverage bottles", and "water bottles"), lifecycle processes (e.g. "production", "recycling", "processing", "mechanical pre-processing", and "consumption"), type of stakeholders (e.g. "petrochemicals industry", "plastic producers", "trade association", "NGOs", "regulators", "customers", "government", "authorities" and "organisation"); and 2) information collation and While internal stakeholders have specific incentives across the PET drinks bottles system (i.e., profit motive for suppliers, shareholders, employees and investors, and convenience for consumers (Iacovidou et al., 2020)), the incentives of external stakeholders are multi-dimensional and depend on the type of engagement (Table 1), the level of information (Section 2.2.2) and the stage of the value chain where they are most active. Based on this hypothesis, we identified and mapped all external stakeholders involved in the complex value creation potential of PET drinks bottles in the UK across the production-consumption-management (P-C-M) system, considering their purpose of establishment, the regional spectrum of their activity (e.g. UK-based, European and international level), and membership, using information obtained from their websites.
The list of external stakeholders that are highly involved in the UK's PET drinks bottles P-C-M system, focusing on recycling, was formed by grouping them according to the criteria below: i. contribution to which /each stage of the PET drinks bottles lifecycle (e.g. from production to consumption (P-C), from consumption to management (C-M), and entire value chain (P-C-

M));
ii. type of engagement (Salvioni andAlmici, 2020, Bammer, 2019) that was specified according to IAP2 spectrum and their activities (Section 2.2.1); and iii. the level of information referring to focus area and sustainability pathway of each stakeholder, using the CVORR 'five levels of information' framework (Section 2.2.2).
It must be noted, that unions (5.E) that are mostly related to framework agreements; competitors (7.E) that refer to shareholders of another plastic material, component, and product value chain (and not of the PET drinks bottles); and media (8.E) that due to their pervasive nature they may be used by other external stakeholders as means to advance their agendas (Banerjee et al., 2003), were not included in our mapping. Via this methodological approach we captured the complex interactions and relationships of stakeholders involved in the PET drinks bottles system in the UK, and were able to generate insights into the way these (relationships) affect the system's performance, and highlight important communication and strategy gaps, presented, described and discussed in Section 4.
We need to clarify that this work constitutes a conceptual analysis of the role of stakeholders in the complex system of PET drinks bottles in the UK and therefore the grouping of external stakeholders following the above-mentioned criteria was based on a stand-alone investigation of social networks of stakeholders (preliminary assessment). Future research could verify these findings by collecting more evidence from primary sources through interviews of stakeholders, following a stakeholder analysis, which can yield insights into the motivation and interests of stakeholders in achieving resource efficiency in the PET drinks bottles value chain in the UK.

Mapping internal stakeholders across the PET bottles value chain
Internal stakeholders (Figure 1) involved in the PET drinks bottles value chain, can be grouped into different categories as they move from upstream to downstream parts of the system due to their transposable roles. According to Freeman et al. (2010), accounting for the changing roles of stakeholders as we move from upstream to the downstream part of the system is the right approach to understanding the dynamics in the system . For example, in the upstream part of the PET drinks bottles value chain (i.e. supply chain), the PET pellets/ preforms/ bottles producers could be the suppliers to drinks manufacturers, whilst drinks manufacturers could be the producers to brand owners when the analysis is on their in-between relationship; yet all of them can be grouped as shareholders when looking at the entire upstream system. Meanwhile, recyclers are considered as suppliers of recycled PET (rPET) either in pellets or preforms (through preform producers) to PET drinks bottles manufacturers upstream of the system, while downstream recyclers become the main shareholders (producers of rPET preforms or pellets).
In Figure 2, we map out the main internal stakeholders involved in the upstream and downstream parts of the PET bottles value chain that constituted the basis for the investigation of power dynamics of all stakeholders involved in the system. It is worth noting, that the categorisation of external stakeholders remains constant across the PET bottles system, and their participation is defined by the stage in which they mostly operate (e.g. production, consumption, management).

Figure 2. Main internal stakeholders upstream and downstream across the system of PET bottles,
after the stakeholder theory (Freeman, 2010).
This mapping exercise uncovered several hurdles with the allocation of internal stakeholders to different types related to: changing roles from upstream to the downstream parts of the value chain (as opposed to external stakeholders), material / product ownership (i.e., PET raw and secondary material / PET bottles), and complex value creation. To address these challenges, we adopted a two-tier classification system for stakeholders when discussing their power dynamics: • Tier one (T1) -refers to the role of stakeholders upstream of the PET bottles value chain; • Tier two (T2) -refers to the role of stakeholders downstream of the PET bottles value chain. Shareholders, these are business organisations whose activities are located in more than two countries and employ both internal and external stakeholders to serve their interests. For simplicity, these are analysed as Shareholders and we refrained from analysing them as part of external stakeholders.

Power dynamics of stakeholders involved in the PET bottles lifecycle in the UK
Efficient and effective communication and collaboration between all stakeholders needs to take precedence to ensure a sustainable complex value creation in the PET drinks bottles value chain. Like Porter (1997) suggests, an effective collaboration that aligns the interests of all stakeholders involved in the value chain can establish a "system of cooperation" where value is created and sustainability is promoted (Porter, 1997). Freeman et al. (2010) suggest that we should not see the interests of each stakeholder in silo, but realise that these are inherently "tied together" and only when viewed as such they can promote value creation in the system .
In the UK plastic packaging value chain, we are far from achieving a "system of cooperation"; as stakeholder interests are not viewed as joint ventures. Employing the CVORR tool, Iacovidou et al.
(2020) were able to look into the role of stakeholders across the plastic packaging system in the UK, and highlighted that to date stakeholders appear to act in silos, and there is a fragmented communication among all stakeholders operating across the plastic packaging value chain. Barrowclough and Deere Birkbeck (2020) argued that in a well-functioning system, stakeholders should collectively identify processes and mechanisms at regional, national and global level to collaboratively harness opportunities to reduce plastic pollution, and be in a position to properly assess the decision-making outcomes. This is in line with Umuhoza et al., (2019) who suggested that real progress can be driven by the wide variety of intergovernmental and industry efforts, strategic partnerships, and environmental advocates involved in the PET bottles lifecycle that act together (Umuhoza et al., 2019).
In Figure 3 we present the interrelationships between the prevalent stakeholders' operating in the UK PET bottles value chain. The PET bottles value chain is largely dominated by multinational corporations, which control significant financial and physical assets and provide thousands of jobs.
This gives shareholders (1.I) significant lobbying power and leverage in negotiations with the government (1.E); hence, they can influence the system at large (Gomes, 2005). Lobbying is defined as the process by which certain groups (e.g. shareholders) influence political decision-making processes by communicating ideas and information relevant to a certain issue to policy-makers (Ihlen andBerntzen, 2007, Jaatinen, 1999). The extent to which shareholders upstream and downstream of the PET value chain (1.I) recognize and integrate environmental issues within their business activities is determined by forces, such as the public's concerns (hence, consumer bargaining power and demands, and changing behaviour/ attitude) (Porter, 1997), regulatory forces (driven by changes in the political and regulatory landscape), competitive edge in the market (controlled via supply-demand dynamics, and substitutability) and top management commitments towards sustainability goals (managers that wield political force and mediate support to shareholders for a certain target) (Lopes de Sousa , Banerjee et al., 2003. Specifically, in T1 (Figure 3), the dominant stakeholders are the petrochemicals industry (4.I) and producers and brand owners (1.I) who are primarily driven by profit. Therefore, their decisions over the design, production and raw materials used in the PET preforms (incl. pellets) and/or bottles production are primarily influenced by factors that minimise operational costs and maximise sales (Freeman, 2010). For example, producers (1.I) will likely choose their materials based on criteria for profit maximisation driven by increased market share and decreased operating costs, while brand owners (1.I) will choose the design of their drinks bottle based on attributes, including branding image, enhanced reputation, and marketability drivers. Both producers and brand owners (1.I) will be influenced by factors related to supply-chain optimisation processes, such as size, and logistics (way of transport and storage). Petrochemicals industry (4.1.) meddles with the supply-demand dynamics as they are coerced to promote their interests and prevent disruptions to their core business processes (Porter, 2008), due to infrastructural lock-in. This lock-in, which is often ignored, prolongs the need for crude oil extraction and refinery, and maintains the petrochemicals industry market share via a continuous oil demand, which tactfully condemns any attempts (e.g. via policy making) to move away from, or reduce the use of, petrochemicals (Ebner and Iacovidou, 2021). This is evident by the current situation emerged due to Covid-19; the glut of cheap oil produced was in high demand by the producers of virgin plastic resins, as it meant lower costs for virgin plastic production and lower prices for virgin plastics that boost competition in the market (Ebner and Iacovidou, 2021).
Furthermore, financial institutions (2.E) put pressure on the petrochemicals industry (4.1) and even more so on the producers and brand owners (1.I) to adhere to the maximisation of shareholder wealth ). In response, they financially support producers and brand owners (1.I) in developing and holding strong lobbying positions in which they can provide policy-makers with insights and information, and in turn influence policy development (Ihlen and Berntzen, 2007).
Due to these dynamics, the P-C system of the PET bottles value chain is naturally-evolved and selfsustaining, e.g., by producers and owners (1.I) acting in their best self-interest. This enables PET drinks bottles producers and brand owners (1.I), petrochemical industry (4.I), and retailers/ wholesalers (5.I) to maximise their profit, while securing the provision of an aesthetically appealing, economically attractive and convenient PET drinks bottle to the consumer (2.I). The harmonisation of regulatory requirements that producers and brand owners (1.I) need to adhere to, is monitored by the UK government (1.E), supranational legislative bodies (1.E), trade associations (6.E), NGOs (3.E) and advocacy groups (4.E) promoting further the evolved marketing of PET drinks bottles. As a result, the adoption of competitive sustainable management strategies in the PET drinks bottles value chain is primarily promoted by external stakeholders. For example, the UK government banned single-use plastic such as straws, stirrers and cotton buds (in effect since October 2020), and proposed a ban on single-use plastics plates and cutlery; yet, these decisions are unlikely to turn the tide on virgin plastic resins demand. Moreover, NGOs (3.E) efforts are placed towards considerably increasing public awareness, creating a sense of responsibility and helping consumers change their behaviour, in order to achieve a reduction in PET bottles consumption and proper disposal (Porter, 1997).
In T2 (Figure 3), we observe a change in the roles of upstream stakeholders (i.e. shareholders in T1 become investors in T2), and introduction of new internal stakeholders (i.e. waste management industry in the role of shareholders). Notwithstanding the efforts of the waste management industry in influencing the policy decision-making processes on single-use plastic ban, plastic waste trade and recycling infrastructure development, these are often at odds with the ideas put forward by producers and brand owners. This undermines the ability of the plastics recycling industry to perform within their profit margins, which could impact on their stability. For example, the steep decline in oil prices caused by Covid-19 has lowered considerably the demand for recycled plastic material, and has put at risk the financial stability of the recycling industry and the waste management industry as a whole.
Disruptions in the ability of the waste management industry to return a profit, could result to a potential reduction in the number of operating facilities, cut in jobs, and compromise investments in new plants and technologies (Ebner and Iacovidou, 2021). This could effectively enhance the technological lock-in and maintain the market for fossil fuel, hence delaying changes required for improving the circularity of plastic waste (Iacovidou et al., 2020). Nonetheless, a coordinated C-M of PET drinks bottles waste needs to be incentivised through national government intervention (1.E).
The introduction of the Plastic Packaging Tax in April 2022 (aims at taxing plastic packaging that contains less than 30% recycled content) appears to be promising in creating a level playing field for the recycling industry. In the absence of national government intervention, consumers (2.I) have little incentive to reduce consumption and dispose of their PET bottles properly. Meanwhile, the waste management industry (1.I) has relatively little financial incentive to engage in the mechanical reprocessing of PET bottles arising from the relatively low profit margins, and the lack of financial support by investors due to the inferior quality of rPET compared to its virgin count part (lower product quality can result to implications in their reputation and profitability margins), sustaining a very low demand for recycled plastics (Ebner and Iacovidou, 2021). This is largely a side effect of the liberal market economy of the UK where there is little government intervention, and where corporations/businesses upstream and downstream (i.e., T1&T2-1.I, T1-4.I, T1-5.I) coordinate their activities mainly through competitive market arrangements (Fifka and Drabble, 2012). As Hall and Soskice (2003) point out, the power of British trade unions (5.E) and the bargaining power of employees (3.I) are both below the average of other market economies (Hall and Soskice, 2009). This signifies that the drive for transitions to a sustainable circular plastics economy can only stem from the market. Indeed, corporations/ businesses (T1&T2-1.I, T1-4.I, T1-5.I), as well as research institutions (9.E), are ahead of the policy debate and efforts to promote circular economy implementation (Hill, 2016). There is now a strong drive from corporations/businesses (T1&T2-1.I, T1-4.I, T1-5.I) to cater for greater accountability and transparency on taking up circular economy initiatives, largely as a reaction to consumer (2.I) expectations due to the rise of the pro-environmental behaviour; thereby, less so due to policy initiatives (Fifka and Drabble, 2012).
This approach seems to be particularly nurtured by the financial system of the UK, which is based on the efficiency of the market and the dynamics between corporations/businesses (T1&T2-1.I, T1-4.I, T1-5.I) that are to solve societal problems (Webb et al., 2016). Moreover, the UK government lacks sufficient resources to cater for the well-rounded information needed in its decision-making process, and provides little financial support to local government (4.I). Therefore their actions towards a sustainable plastic waste management, including that of PET bottles, depends on private businesses investments that are not always directed towards sustainability (Porter, 1997). Hence, public investment in waste infrastructure assets and innovative technologies is limited, and the management of plastic waste is carried out largely through private companies. Consequentially, this creates a technological lock-in where businesses show a preference to well established technologies, and local government (4.I), which from now we will refer to as Local Authorities (LAs). LAs (4.I) are trapped into the long contracts they make with waste management companies, struggling to constitute a legitimate space and rationale for intervention. Financial institutions (2.E) engage in limited risk sharing for new technology investments in a rapidly evolving market, such as that of plastics (Hill, 2016).
Policy instruments, such as taxes, and incentives (e.g. via the deposit return schemes) and price-based measures (e.g. imposed via refill stations) can if effectively implemented bring changes in the dynamics between upstream and downstream stakeholders. In this realm is the extended producer responsibility (EPR) schemes, which were introduced to place responsibility for the management of post-consumer PET bottles on producers / brand owners (T1-1.I), and also, handlers, i.e. retailers and wholesalers (T1-5.1) of plastic packaging. EPR schemes aim to cover the cost of the EoL management of post-consumer packaging products (incl. plastics) and incentivise the waste management industry (T2-1.I), whilst demonstrating the commitment of producers / brand owners (T1-1.I) and handlers (T1-5.I) of plastic packaging to conform to the regulations and take responsibility in supporting recyclability and waste reduction; a process that is usually carried out via intermediary organisations (PRO: producer responsibility organisation) (6.E) (Hahladakis et al., 2018a, BPF, 2021a (BPF, 2021a). PRNs/ PERNs are certificates that indicate a tonne of plastic packaging has been recycled, recovered or exported, and are traded between waste management industry (T2-1.I) (i.e. UK accredited reprocessors and exporters) who are allowed to issue and sell PRNs/PERNs, and the intermediaries that act on behalf of the producers / brand owners (T1-1.I) and handlers (T1-5.I). These exchanges take place in an open market, and therefore PRN/PERN prices fluctuate depending on supply and demand (Matsueda and Nagase, 2012). The current EPR implementation in the UK, and the way the PRNs system currently operates creates mistrust regarding the sale of evidence notes and the way income therefrom supports the recycling of plastic packaging waste (Iacovidou et al., 2020).
In addition to that, plastic pollution is largely perceived as "out of sight and out of mind", as large amounts of plastic waste are exported for recycling to other lower income and/or lower consumption countries shifting the problem elsewhere (Barnes, 2019). The phenomenon of plastic waste exports has led to short-term improvements locally by promoting changes in the collection regimes or awareness raising campaigns, and long-term implications as a result of underestimating plastic waste mismanagement in the exporting countries (Barnes, 2019). In 2017, the Chinese government banned the import of plastic waste, and western governments including the UK, were forced to confront the problem urgently (Noritake, 2019, Vollmer et al., 2020, Wen et al., 2021. Notwithstanding the efforts of the national government (1.E) to control the plastic packaging sector's activities, its role is constrained by the well-established market of the PET drinks bottles. Any political strategy related to product replacement, increase of product cost, or adoption of recycled product needs to be supported by producers and brand owners (T1-1.I) and consumers (2.I).
Producers, brand owners and consumers are in a particularly strong position to motivate the adoption of bans and/or promote the use of recycled content and introduction of rather expensive alternative materials, but they can equally act as barriers by expressing opposing viewpoints, or simply not supporting, these ideas and practices (Jansson et al., 2017).A characteristic example was the resistance in adopting the proposal of the EC regarding the mandatory tethered caps in plastic drinks bottles by well-established brand owners (T1-1.I) such as Coca-Cola, Danone, Nestlé, and PepsiCo (Nielsen et al., 2020). Moreover, public acceptance prevents the national government (1.E) from applying high pressure on producers and brand owners (1.I) who have a power over multifaceted voters. For example, influential voters include workers in the PET bottles production and drinks manufacturing industries (T1-3.I) that are worried about their jobs, and consumers (2.I) that are concerned about the environment and human health, and are simultaneously wary of the affordability of consumer goods.
The step-up in the PET bottles recycling activities is strongly influenced by the relationships of LAs imperative to understand barriers so that LAs (T2-4.I) can fine-tune their campaigns to influence consumers (2.I) behaviour towards supporting their recycling efforts (Joseph, 2006). This requires decent planning which in turn requires substantial financial resources that LAs do not currently have access to. For many years, national government (1.E) had a significant power over LAs (T2-4.I) in England, as they controlled directly and indirectly their economic resources via revenue support grants. This revenue support is slowly being phased out, and LAs (T2-4.I) have faced a reduction to their funding from the Government of nearly £16 billion since 2013 (LGA, 2018). This has brought changes in the ways LAs (T2-4.I) operate, including cuts in the budget allocated for waste management. In turn, this has also led LAs to revert to insourcing their waste services, or creating partnerships with other LAs to minimise the costs. The impact of these partnerships to sustainable waste management remains uncertain. To this end, the way the EPR is currently being practiced overburdens LAs (T2-4.I) with the cost of collection and management of plastic packaging waste, offers very little (if any) cost compensation, whilst it hampers infrastructure investments due to financial risks. Apart from introducing well-designed EPR schemes and well-coordinated bans and taxes, the most effective act on the part of the national government (1.E) would be to push for expanding the recycling infrastructure.
In relation to the latter (increasing recycling capacity in the UK), NGOs (3.E) are ringing the alarm for political groups to start implementing measures that in the long-term can support the recycling of a bigger fraction of PET drinks bottles. The UK currently does not have the capacity to deal with the cumulating and ever-increasing amount of plastic waste generated, including PET drinks bottles. Yet, PET drinks bottles are considered to be a relatively 'clean' plastic waste stream presenting an opportunity for the UK to increase its recycling rates given that it is properly collected and sorted.
Investments in increasing the recycling capacity are considered nonsensical from an economic point of view, but with exporting becoming problematic and the incumbent regulatory reforms that will mandate an increase in the use of rPET, such investments might become feasible in the near future. To that end, the ability of legislative bodies (1.E) to control and monitor these changes and enforce regulations remains a major issue.
The UK government (1.E) has promoted its scientific-oriented agenda via expanding its research grants portfolio and therefore establishing a well-functioning relationship with research institutions (9.E). Research institutions (9.E) make a significant and valuable contribution to knowledge building via: synthesising existing knowledge and new research findings to explain systems or phenomena; creating new understanding of the interconnections between stakeholders, sectors and systems; and managing unknowns to support problem-solving and inform change. And yet, they have very limited control over the practicalities and capabilities needed to internalise this knowledge building into policy-and decision-making processes (Bammer, 2019). Industry associations (6.E) are able to bring together shareholders from both parts of the value chain (T1&T2-1.I) with research groups (9.E), and aid the adoption of policy-relevant research agendas on transitioning PET bottles value chain in circular economy (Barrowclough and Deere Birkbeck, 2020). Science-based stakeholder dialogue can link research with knowledge domains outside academia, and therefore it should be perceived as a representative practice of thinking together rather than as a substitute for scientific thinking (Welp et al., 2006). towards creating credit for desired plastics alternatives and substitutes, promoting "a sustainable transformation away from environmentally and socially degrading economic processes" (Barrowclough and Deere Birkbeck, 2020).
Previous stakeholder analyses in the waste management sector (T2-1.I) found that the influence and participation of all stakeholders, both internal and external, is a prerequisite for the transition towards a more sustainable economy and their role should be tracked over a time period considering current situation (Joseph, 2006, Heidrich et al., 2009. The current production, technological, and regulatory lock-ins in the PET drinks bottles value chain are making the system incapable of change by itself due to economic factors (e.g. using primary materials in PET bottles production is cheaper than using rPET), socio-technical arrangements (e.g. PET drinks bottles are able to provide freshness, convenience, safety, and accountability in everyday life (Evans et al., 2020)), lack of incentives for recycling downstream. This situation indicates the need for a close collaboration amongst all external stakeholders involved in the PET drinks bottles value chain in liaise with all internal stakeholders. On the one hand, the overemphasis on consumers' (2.I) behaviour and household practices which is currently trending in policy, industry and research fields may lead to an underestimation of the problem, and will be plainly insufficient to address the low plastic recycling rate (Evans et al., 2020).
On the other hand, greater attention to the design and technical attributes and performance of PET drinks bottles shifts attention from their EoL fate and the changes that they may undergo during their lifecycle, which are key to understanding quality aspects, unintended consequences and improving their recycling rates (Hahladakis and Iacovidou, 2019).
It is thus evident, that gaining an improved understanding of the dynamics upstream and downstream in the value chain of PET drinks bottles, it is a noteworthy and necessary starting point in aiding the transition towards to a more sustainable plastics economy. Regulators and local government need to work together with brand designers, manufacturers, importers, wholesalers, retailers, waste management companies, recyclers, consumers and other organisations (e.g. trade-unions, associations, NGOs). This would help to coordinate their actions, and make it feasible to maintain progress in waste and resource management; to promote technological innovation and investment; to implement transparent environmental policies; and to use information-based instruments to raise the social responsibility of businesses and individuals.

External stakeholders and their role on making the transition to a circular plastics economy
Black et al. (2019) reported that PET drinks bottles producers and brand owners (T1-1.I) and reprocessors (T2-1.I) are tied-up in the investments they made to improve their processes, such that any change will likely cause financial damage. In this respect, the mission of the external stakeholders involved in the plastic packaging value chain is to provide: i) transparency in the system and access to data for monitoring and investigating trends in PET bottles production, trade, and distribution in the economy across P-C-M; ii) set up easy to achieve, measurable sustainability targets and standards to promote better management; and iii) develop financial and policy levers to support the implementation of i) and ii) (Barrowclough and Deere Birkbeck, 2020).
Transparency can provide clear insights on where / how PET preforms / bottles / drinks are imported, produced, filled, and placed on the UK market, as well as how many of the PET bottles are recovered for recycling, and how many are exported. At the stages of sorting and reprocessing, a constant and transparent monitoring of PET bottles flows at each stage of value chain is required to account for the losses/rejects in the system, and identify hotspots for intervention. This type of granularity in the system, may require a lot of scrutiny that is time-consuming, but as Hopkinson et al. (2018) suggest it is a necessary step towards the adoption of a circular economy; streamlined via "investment in information management and tools to manage complex system dynamics and anticipate future scenarios (p.91)".
To date, there is a long list of external stakeholders in the UK ( national, and regional level in a rather fragmented manner (Nielsen et al., 2020). Trade associations (6.E), that exhibit self-organisation and dynamism, emerge from a multiple supply network, that is built upon complex adaptive collaborations usually on short-to medium-term supply risks, which tend to be relatively opportunistic and ad hoc (Azadegan and Dooley, 2021). Their main priority is to align their members with the national and European regulations to support the development of a sustainable system of PET bottles, whilst preserving their financial interests. The main challenge for trade associations (6.E) is to harmonise expectations between their members which may often be opposing.
For example, the members of British Plastics Federation (BPF), that focus on the entire PET value chain include both manufacturers and recyclers, whose financial interests might be opposed from the perspective that PET bottles production from primary raw materials (e.g. oil) might be a more affordable option than this of secondary materials (e.g. rPET preforms) (Ritchie, 2018 engage plastic production and consumption on a systemic level since they mainly focus on simple plastic items that are easy to regulate and reprocess (easiest objects are usually targeted), while more complex objects remain unaddressed (Nielsen et al., 2020). This situation might be attributed to the fact that NGOs (3.E) may partner up with government (1.E) that is strongly lobbied by shareholders (1.I), and therefore NGOs are steered by government towards a 'specific' direction.
Governmental bodies (1.E) focus on certain areas including practices and strategies related to resource efficiency, EoL management, and waste generation reduction. However, little attention is paid to strategies that encourage the development and change of behaviour (e.g. social awareness), the redesign of current unsustainable processes (e.g. production of complex plastic items) and alternative operational processes in line with the circular economy concept (Klein et al., 2020). The need to focus on these strategies becomes critical when one considers the increasing embedment of PET bottles in the food market practices (e.g. meal deals and packed lunch ideas that are fully convenient for on-thego consumption always include a soft drink bottle). Concurrently, the multi-dimensional limitations of the use of alternative materials enhance the centrality of food plastic packaging in contemporary economic and social trends (Evans et al., 2020). This situation emerges from commercial, technological, regulatory, and social-culture elements, and the increased promotion of a lifestyle that is based on convenience and overconsumption (Evans et al., 2020). The strong lobbying position of producers and brand owners (T1-1.I) is reflected by the influence they have over consumers (2.I) preferences (via attributes such as freshness, convenience, safety, accountability and affordability).
A list of most prevalent external stakeholders, that have potentially a pivotal role in making the transition of PET bottles in the UK to a circular economy, grouped according to these influencing factors (type of engagement, level of information, and stage of value chain) and stakeholder category (Figure 1), is provided in Figure 4 (raw results are provided in Table A

Production-Consumption (P-C)
In the P-C stages of the PET drinks bottles value chain in the UK, the influence of external stakeholders is lesser than downstream (C-M) ( The absence of the inform type of engagement, hinders the creation of complex value and the transition to sustainable PET bottles management. Although inform is the lowest level of engagement, it constitutes the main pillar to building upon the other types of engagement. Therefore a balanced proportion of all types of engagement in the system is required for an effective strategy development towards circular economy (Salvioni andAlmici, 2020, Asari, 2019). For instance, research institutions (9.E) suffer from the lack of generation of tangible research impact and fail to establish networks for the dissemination of scientific findings, and research support. This has a direct impact on producers and brand owners (T1-1.I) who miss opportunities for knowledge transfer and information access that could help them reconsider and revamp their business models and improve their decision-making processes. Similarly, the absence of collaborate type of engagement is symptomatic of the inertia of external stakeholders in making improvements to the upstream part of PET bottles value chain. This is reinforced by the regulatory framework and political landscape (3 rd level of information) and the way the market operates in the UK (4 th level of information), which in turn, has a direct impact on the provisioning services and the environment (1 st level of information) and the political landscape (with focus on the regulatory compliance with standards related to PET bottles in contact with food) (3 rd level of information).
Henceforth, governmental bodies (1.E) appear to be the prevalent external stakeholders operating in the P-C stages of the system followed by trade associations (6.E) (Figure 5). These observations are exemplified by the fact that the P-C stages are able to serve the needs of internal stakeholders, and therefore, interventions aimed at imposing sustainability measures on the PET drinks bottles system are limited. The absence of efforts towards change on the plastic packaging upstream in the system has also been reported by (Barrowclough and Deere Birkbeck, 2020).

Consumption-Management (C-M)
In the stage of C-M there is larger and multi-faceted participation of external stakeholders (Figure 6) compared to P-C stages. The majority of external stakeholders participate in the C-M stages through the consult engagement type, and are mostly composed of trade associations (6.E), and some NGOs (3.E). Trade associations (6.E) role in C-M is more active and broader than NGOs' (3.E) due to their main incentive to protect the interests of their members ( Table 2) Whilst, governmental bodies (1.E) appear to have gained traction on the empowerment type of engagement (Figure 6), the varying capacities and broad capabilities of shareholders downstream (T2-1.I) cannot guarantee that targets to improve PET bottles recycling rates are going to be met. This is due to the complex and dynamic factors related to technological innovations and the market volatility induced by the transition (Hopkinson et al., 2018), as well as the absence of incentives needed to mobilise a more sustainable consumer behaviour. To date, governmental bodies (1.E) attention has been placed to providing guidance on best available techniques and technologies used by the waste management industry (T2-1.I) and strategies for waste prevention and recycling improvement (4.I). Nonetheless, the role of governmental bodies (1.E) is highly critical at the stage of EoL management of PET bottles and therefore a more active and effective intervention is required to improve consumer consumption/ disposal practices, and the waste management infrastructure for promoting PET bottles recycling.
Finally, NGOs (3.E) appear to be particularly active through the inform function, even though their role in the consult type of engagement is limited (Figure 5(B)). NGOs activities are placed on informing and educating consumers, altering their purchasing habits and promoting behaviour change (5 th level of information), in order to preserve the natural environment via reducing the amount of PET drinks bottles placed on the market, whilst simultaneously preventing environmental impacts associated with their (mis)management (1 st level of information) (Figure 5(A)). In isolation their activities cannot be far-reaching; collaboration with governmental bodies (1.E) and trade associations (3.E) can be instrumental to creat the enabling condition for promoting sustainable management of PET drinks bottles across all levels of information.

Production-Consumption-Management (P-C-M)
The participation of external stakeholders is greater in the whole PET bottle value chain (P-C-M), (Figure 7) as involve and collaborate engagement strategies are employed by trade associations (6.E) and government bodies (1.E) for all levels of information, with a focus on infrastructure and innovation (2 nd level) and business practices and market (4 th level) (Section 2.2.2). This suggests that external stakeholders encourage shareholders (T1&T2-1.I) to transform their practices towards sustainable circular plastics economy are mid-way to creating tangible impact. To that end, research institutions (9.E) and NGOs (3.E) have a critical role to play in nurturing multilateral collaborations needed to increase the circularity potential of PET bottles via the inform and consult functions that seek to inform, educate, influence perceptions and change behaviours.
In the UK, UKRI (9.E) is the leading research body that develops partnerships of universities (9.E) and research organisations ( the category of external stakeholders (Figure 1)

(B).
A coordinated participation of all external stakeholders in the system through consult and inform engagement is required to access existing knowledge and technologies, and create new knowledge; a prerequisite to move towards involve, collaborate and empower stages of engagement. To date, as indicated by Figure 4 and 5, attention has been largely focused on the downstream part of the system.
Focusing on one part of the system (in this case, downstream) however, entails the risk of distraction from other problematic social and environmental arrangements in in making improvements in PET drinks bottles recycling (Evans et al., 2020).

Conclusions
The study revealed both theoretical and practical implications when unpacking the complexities of the plastic packaging value chain. Stakeholder theory can go beyond the social sciences boundaries, and provide a lens with which we can understand stakeholders' role and importance in environmental engineering and policy fields. We showed that the integration of stakeholder theory to a systemsbased approach like CVORR can generate critical insights via breaking through the disciplinary silos.
This not only can extend the theoretical application of the stakeholder theory, but it can also offer a transdisciplinary lens to assessing resource recovery systems via its integration with the CVORR approach.
In the UK, PET drinks bottles belong to a well-established liberal market where producers and brand owners (internal stakeholders operating upstream of the value chain) have a significant lobbying power over the entire value chain, and are strongly supported by financial institutions and retailers /  wholesalers. The main practical implication arising from this dynamic is an ever-increasing attention at the downstream part of the value chain, which is further nurtured by external stakeholders that lack the power and incentives to shift attention upstream. By focusing on the downstream part of the system, we revealed inefficiencies that are often allotted on the technological lock-ins, the inability of the waste management sector to comply with the regulations, or on the constrained ability of local government to influence (and increase) consumers' participation in the recycling schemes, and make changes in the collection and management infrastructure. These inefficiencies are further promoted by external stakeholders (e.g., trade associations, NGOs and research institutions), that find it easier to go for the low hanging fruits and spur activities mid-stream (e.g., focus on changing consumers behaviour), and/or downstream (e.g., focus on improvements in waste management infrastructure) of the value chain.
While producers, brand owners and suppliers reap the benefits of the ever-increased demand for PET drinks bottles in the market, the local government and waste management industry (internal stakeholders operating downstream of the value chain), are burdened with the costs and accountability to conform and meet the targets set by the UK government. This dynamic presents many challenges to the waste management industry, whose issues are often being ignored. The strife to improve the collection and management of PET drinks bottles by way of promoting circular economy needs to be matched by policies and market-based instruments that support local government and waste management industry, and control the volatility in the prices of virgin and recycled commodities.
The lack of political tenacity and strategic direction and innovation that tackles inefficiencies in the whole system can severely restrict the ability to close the PET drinks bottles loop. Policy-makers need to create a level playing field by giving all stakeholders access to the development of policies. They also need to introduce mechanisms that can mediate the ideas that are passed on their agendas. In that way, they can gain a balanced perspective on the PET bottles value chain and thereby formulate effective policies. This can increase the integrity and transparency of the decision and policy making process and counterbalance all stakeholders' interests. It is at the best interest of local government and businesses alike, to rethink their business models and introduce technological innovation that help them transform, and comply with the EPR regulations (e.g. advanced collection systems such as DRS and/or refilling market stations). The value proposition offered by these innovations can build trust between consumers and businesses and establish rapport over capturing value from plastics (PET bottles).
Finally, the study highlights the importance of a well-coordinated stakeholders' network to achieving a transition to a sustainable circular plastics economy. Henceforth, a holistic understanding of the dynamics involved in the plastic packaging system, in a specific spatial (global, national, local) and temporal (annual, five-year period, etc.) context, is crucial to seizing the multi-dimensional benefits of the proposed interventions, and making it possible to transition to a sustainable circular plastics economy. Both theoretical and empirical approaches need to be employed to ensure success in finding common ground, uncovering hidden aspects and making real progress on improving the PET drinks bottles recycling in the UK.