UK Plastic Packaging Tax: Preparing for Mass Balance in April 2027

Know what mass balance establishes

Mass balance attributes chemically recycled input to outputs from a system that also handles virgin material. HMRC’s guidance requires third-party certification meeting the tax scheme’s minimum requirements. It does not offer this accounting route for businesses using only mechanically recycled plastic.

The Plastic Packaging Tax overview describes the tax as applying to finished packaging components containing less than 30% recycled plastic, subject to the tax’s scope and exclusions. An attributed chemical-recycling claim therefore needs to connect to the relevant component and its supporting records. It should not be mistaken for physical segregation of recycled polymer in each item.

Keep three descriptions separate in a purchasing system: mechanically recycled material, chemically recycled material with qualifying attribution, and virgin material. This is an internal recordkeeping recommendation; agree the actual tax classification with the team responsible for the return.

For a different resin-supply example, see our coverage of Plastipak’s single-pellet rPET for thermoforming. Compare the evidence behind each route instead of grouping every recycled-content claim into one field.

Map the chain before approving a supplier

Under HMRC’s preparation guidance, relevant supply-chain businesses from the chemical recycler through the packaging converter must be certified. A business that only imports finished packaging need not itself be certified, but must hold supplier evidence and check the certified chain.

Map that chain for each proposed material and packaging source. Name the organizations and sites responsible for recycling, intermediate processing, polymer manufacture and conversion. Ask the direct supplier who can provide evidence of the earlier stages. Resolve gaps before entering an annual supply agreement.

Assign a person to maintain the map. Purchasing may select the resin, technical staff may qualify it, and finance may prepare the return. Someone needs to connect their records so that a change of converter or manufacturing site reaches all three teams.

Check the certificate and delivery declaration together

HMRC’s minimum requirements for businesses require certificates to identify covered addresses, validity dates and materials. Each delivery or batch needs an attribution declaration, renewed when material passes between supply-chain businesses. The declaration includes the attributed quantity, a unique batch number, dispatch date, and supplier and recipient details.

Turn those fields into a receiving check. Match the delivery to the purchase order, certificate scope and declaration. Keep the documents together using the supplier’s batch identifier and your own receipt reference. If the material arrives at a different site or under a different grade name, resolve the mismatch before recording attributed content.

The requirements for certification scheme operators include an electronic register for checking certified businesses. Ask the supplier for the register entry as well as a certificate file. Confirm what the certification covers, rather than relying on a logo in a sales presentation.

Understand the site-level accounting rules

The business requirements specify a three-month balancing period, with no negative balance at any point. They also require site-specific conversion factors and fuel-excluded attribution where processes produce fuel-use outputs. Records must be retained for six years, including certificates, batch declarations and site-level mass-balance records.

A buyer does not need to reproduce every upstream process calculation to compare quotations. It does need to know who owns those calculations, which scheme verifies them and how the supplier will support a query. Include that support requirement in the commercial review.

For converters seeking certification, involve production planning and stock control early. Build a trial record using actual material receipts, production orders, losses and dispatches. Check whether the information can be reconciled without someone reconstructing it from separate spreadsheets after the quarter closes.

Keep other packaging approvals in their own files

Tax attribution does not, by itself, demonstrate food-contact suitability or packaging recyclability. When specifying a tray, bottle or closure, retain the technical and regulatory evidence needed for those separate uses. A certified attributed-content figure answers a different question from seal performance, migration or compatibility with a recycling stream.

Use the thermoforming company directory and blow-molding company directory to identify potential production partners, then send them the same material and documentation brief. Their listing is a starting point for supplier research; check the proposed supply chain directly.

Use the months before April for a document trial

HMRC says more detailed guidance is due in early 2027. Schedule a review when that guidance appears and before the first affected return.

Meanwhile, request a sample certificate, attribution declaration and delivery record from each proposed supplier. Route them through purchasing, goods receipt and the tax team. Test what happens when a document is missing or the batch identifiers disagree. Fixing that handoff now gives the April 2027 start a workable process behind it.