5 Common Plastic Packaging Tax Mistakes That Will Trigger an HMRC Audit
If you're a UK business importing or manufacturing plastic packaging, the Plastic Packaging Tax is on HMRC's radar — and so are you. Here are the five mistakes that consistently get businesses caught out.
HMRC Is Actively Auditing PPT Registrants
Since April 2022, HMRC has been systematically auditing businesses to ensure compliance with the 10-tonne threshold and 30% recycled content requirements. Most businesses don't realise they've crossed into taxable territory until HMRC sends the audit letter — by then you're facing backdated tax bills, penalties up to 100% of unpaid tax, and potential interest charges dating back years.
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Calculating the 10-Tonne Threshold Incorrectly (The "Just Under" Trap)
The Mistake
Businesses assume the 10-tonne threshold applies to finished goods only — so they ignore components, transit packaging, and imported packaging. They calculate 9.8 tonnes and think they're safe.
The Reality
HMRC counts all plastic packaging you're responsible for in a 12-month rolling period, including:
Real example
A Manchester e-commerce business calculated 8 tonnes of mailer bags. HMRC audit revealed they'd imported 3 tonnes of protective bubble wrap and held 1.5 tonnes of seasonal stock. Total: 12.5 tonnes. Backdated liability: £3,125 plus penalties.
Why HMRC Targets This
HMRC cross-references your PPT declaration against:
If your tonnage seems suspiciously close to 9.9 tonnes year after year, expect an audit.
How to Avoid
Use the rolling 12-month calculation method. On the 1st of each month, total the previous 12 months' packaging. If you breach 10 tonnes, you have 30 days to register for PPT. Don't wait until year-end — you could owe tax from the month you crossed the threshold.
Claiming Recycled Content Without Proper Evidence (The "Supplier Said So" Defence)
The Mistake
A business orders packaging from a supplier who states "30% recycled content" on the invoice. They claim the exemption and pay no tax. HMRC audits them 18 months later and rejects the claim because there's no independent verification.
The Reality
HMRC requires one of these evidence types:
Option A: Mass Balance Certification
Third-party audit trail showing recycled content throughout supply chain. Accepted certifications: ISCC PLUS, REDcert, RSB.
Option B: Sampling & Testing
Laboratory analysis of packaging samples. FTIR spectroscopy or similar methods. Test reports from UKAS-accredited labs.
Option C: Direct Production Records
If you manufacture packaging in-house: production run records showing virgin vs recycled resin input, and monthly reconciliation reports.
A supplier invoice alone is NOT sufficient.
Real example
A Birmingham fulfilment company claimed £18,000 recycled content exemption based on supplier statements. HMRC demanded mass balance certificates. Supplier couldn't provide them. Company paid £18,000 tax + £9,000 penalty + interest.
How to Avoid
If you've already claimed exemptions without evidence, file a voluntary disclosure now before HMRC audits you. Penalties drop from 100% to 0–30% if you self-correct.
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Check My PPT ComplianceIgnoring Import Liability (The "It's Not My Problem" Assumption)
The Mistake
A UK business imports packaging filled with product from China. They assume PPT is the supplier's responsibility because the packaging was manufactured overseas.
The Reality
If you import finished packaged goods or unfilled packaging into the UK, YOU are liable for PPT — even if you never manufactured or filled the packaging yourself.
This catches out:
You're the "importer" if:
Real example
A London cosmetics distributor imported 15 tonnes of plastic bottles from Italy (filled with product). They thought PPT only applied to UK manufacturers. HMRC audit: £45,000 backdated tax + penalties.
How to Avoid
Failing to Keep Adequate Records (The "I'll Remember" Trap)
The Mistake
A business registers for PPT, files quarterly returns, but doesn't maintain a proper audit trail. When HMRC requests records 2 years later, they piece together invoices, emails, and spreadsheets — but can't reconcile figures. HMRC assesses "best judgement" tax, which is always higher than actual liability.
Mandatory Records You Must Keep for 6 Years
Format: Digital or paper is acceptable, but must be produceable within 30 days of HMRC request.
How to Set Up a PPT Record System
Option 1: Manual Spreadsheet (Small volumes)
Monthly log: Date | Supplier | Product Code | Tonnage | Recycled % | Certificate Ref. Include a running 12-month total and a folder of supporting certificates/invoices.
Option 2: Automated System (10+ SKUs or 50+ tonnes/year)
Integrate with procurement software to auto-extract packaging weight from purchase orders, link to a certificate database, and generate quarterly return data automatically.
Option 3: Outsource to Compliance Specialist (100+ tonnes/year)
Submit invoices/import docs monthly. Compliance team maintains records, files returns, and provides HMRC audit defence.
Red flag to HMRC
Businesses that file identical tonnage every quarter (e.g., exactly 2.5 tonnes Q1–Q4). It suggests estimates rather than actual records. Expect an audit.
Misunderstanding the "Unfilled Packaging" Export Exemption (The "We Ship Overseas" Loophole)
The Mistake
A UK manufacturer produces plastic bottles and exports them unfilled to an EU customer. They claim full PPT exemption, assuming all exports are exempt. HMRC audits them and denies the exemption.
The Reality
The export exemption only applies if:
What doesn't qualify:
Real example
A Sheffield manufacturer exported 12 tonnes of plastic caps to Ireland. The Irish customer filled them and sold products back into the UK. HMRC ruled: No exemption. Manufacturer owed PPT because packaging was ultimately used for UK supply.
How to Avoid (For Genuine Exports)
Complex supply chains (manufacturing in UK, filling overseas, selling back to UK): you likely owe PPT upfront on manufacture. Seek specialist advice — HMRC's interpretation is strict.
What Happens If You're Audited?
Information Request
HMRC requests 12–24 months of records with a 30-day response deadline. Extending the deadline makes you look guilty — respond on time.
Review Period
HMRC analyses submissions, identifies discrepancies (tonnage gaps, missing certificates), and may request additional evidence.
Assessment
HMRC issues preliminary findings, states additional tax owed plus penalty calculation, and gives 30 days to dispute.
Resolution
Accept: pay tax + penalties + interest. Dispute: provide counter-evidence or request internal review. Worst case: Tax tribunal (6–18 months, legal costs £10K+).
Typical Penalties
How to Audit-Proof Your PPT Compliance
Quarterly PPT Health Check
Every 3 months, review:
Red Flags HMRC Looks For
The Cost of Getting It Wrong vs Prevention
Cost of Getting It Wrong
Cost of Prevention
Final Thought: HMRC Is Getting Smarter
HMRC now uses data analytics to identify PPT non-compliance:
The audit net is tightening. If you're not compliant, it's not "if" HMRC finds you — it's "when."
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Contact Us for Urgent SupportLast updated: February 2026 | Based on HMRC PPT guidance and enforcement activity data