From April 2027, the UK government will introduce one of the most important and potentially controversial changes yet to the Plastic Packaging Tax (PPT).
On the surface, it sounds technical. Chemically recycled plastics will be allowed to count toward the 30% recycled content threshold needed to avoid PPT and businesses will be permitted to use a ‘mass balance accounting’ system to allocate recycled content across plastic outputs but underneath the accounting language lies something so much bigger:
The UK is quietly redefining what counts as recycling.
From 1 April 2027, chemically recycled plastic will officially count as ‘recycled content’ for Plastic Packaging Tax purposes. Businesses will be able to use mass balance accounting to allocate recycled content across plastic production systems.
Pre-consumer waste such as factory offcuts, trim waste and in-house production scrap will no longer count as recycled content for PPT purposes and that final point is more significant than it first appears.
For years, manufacturers could effectively count portions of their own production waste as ‘recycled content’. From 2027, the government is drawing a philosophical line: - Reusing your own manufacturing waste is now being treated as normal good practice; not recycling and that is a notable shift toward rewarding genuine post-consumer recovery rather than internal process efficiency.
Why Is Government Supporting Chemical Recycling?
The answer lies in the uncomfortable reality of modern packaging design. Some packaging formats were never realistically designed for mechanical recycling in the first place. Flexible films, laminated pouches, multi-layer barrier packaging, food-grade plastics contaminated with oils, residues or adhesives - these materials create major operational problems within traditional recycling systems; contamination, difficult separation, expensive washing requirements, weak resale value and complex polymer mixes.
While simple packaging formats such as aluminium cans, steel and cardboard often retain strong intrinsic recovery value, many modern plastic packaging systems do not, so rather than redesigning all packaging into simpler mono-material formats, governments are increasingly supporting technologies designed to recover value from difficult plastics through chemical processes such as pyrolysis and depolymerisation and that’s the real significance of the 2027 PPT reforms.
What Is ‘Mass Balance Accounting’?
In many chemical recycling systems, recycled and virgin feedstocks are mixed during production. The recycled content is then allocated mathematically through an accounting model across different plastic outputs which means a plastic product may legally qualify as containing ‘30% recycled content’ even though the molecules within that specific item may not physically contain 30% recycled material.
In effect, the system tracks recycled content through paperwork as much as through polymer.
· Supporters argue this is a practical and necessary way to scale chemically recycled plastics within existing petrochemical infrastructure.
· Critics rightly argue in my opinion that it risks creating a system based partly on accounting allocation rather than direct physical traceability.
That tension sits at the centre of the debate. To supporters, mass balance accounting is simply the next evolution of recycling infrastructure. It may (in theory) unlock investment in advanced recycling; help process difficult plastics previously destined for energy recovery or landfill, support food-grade recycled plastic applications; even accelerate recycled-content targets but critics worry the system could (will) become increasingly difficult for consumers and even businesses to meaningfully understand.
If recycled content is being allocated mathematically across production systems, then the question begins to emerge - are we measuring actual recycling or confidence in accounting systems? That does not necessarily make the system illegitimate, but it does move recycling into a far more complex territory than the traditional public understanding of ‘this bottle became another bottle’.
The Bigger Packaging Question
The reforms also expose a deeper issue within the modern packaging economy. Over the last two decades, packaging has increasingly evolved toward lightweight composites, laminated barriers, convenience-focused flexible films, highly engineered shelf-life optimisation via multi-material formats difficult to separate mechanically. Many of these innovations improved product performance, reduced transport emissions and extended food life but they also made recycling significantly more complicated.
Chemical recycling may ultimately become part of the solution however there remains a difficult question underneath the tax reforms and accounting systems - are we now redesigning packaging to fit recycling or redesigning recycling policy to accommodate problematic packaging?
That debate is only just beginning.
The nervousness surrounding wider recycling support mechanisms such as PRNs hints at an even larger issue sitting quietly behind the sector.
None of this means chemical recycling is unnecessary. Without technological and financial intervention, large parts of the modern plastics stream may remain commercially or technically difficult to recycle at all but the 2027 PPT reforms represent something far larger than a tax adjustment; they signal a transition in how governments may increasingly approach circularity itself: not purely as a physical process of recovering materials but as a system supported by chemistry, policy, accounting models and economic intervention and that raises one final question:
· At what point does circularity remain a physical process of recovering materials?
· At what point does circularity become a mathematical allocation model designed to compensate for packaging that was never circular to begin with?













