Guide
Correct a customs declaration error or make a voluntary disclosure
How to amend a customs declaration after goods have been released, or make an unprompted voluntary disclosure of historic underdeclarations to HMRC. Covers the C2001 route, the National Clearance Hub route for systemic errors, and the penalty mitigation available when you tell HMRC before they ask.
If you find a mistake on a customs declaration after your goods have been released — wrong commodity code, undervalued invoice, missing royalty payment — you must tell HMRC and pay any underpaid import duty and import VAT. Telling HMRC before they ask is a voluntary disclosure and usually reduces the penalty to nil.
This guide covers errors on declarations you have already submitted. If your goods are still in transit and you spot an error before release, ask your customs intermediary to amend the entry through CDS before clearance.
When this guide applies
Use this guide if you are the declarant or the importer of record and you have identified one or more of the five most common error classes:
- Wrong commodity code (incorrect tariff classification)
- Under-valued goods — missing additions required by regulation 130 of SI 2018/1248, such as royalties, licence fees, selling commissions, or freight to the place of introduction
- Wrong customs procedure code (CPC) — for example using free circulation when goods should have entered a special procedure
- Incorrect preference claim — origin rules of the relevant trade agreement were not in fact met
- Failure to account for goods removed from a special procedure (inward processing, customs warehousing, temporary admission)
Unprompted disclosure mitigates the Schedule 1 penalty
2003 and Schedule 1 is to mitigate the civil penalty for inaccuracy
— often to nil — where you make an <strong>unprompted</strong>
voluntary disclosure before HMRC has opened an enquiry. If HMRC
has already written to you about the period in question, the
disclosure is <strong>prompted</strong> and full penalties up to
£2,500 per contravention (or £1,000 for minor errors) can apply.
The duty, VAT and interest remain payable in both cases.</p>
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1. Scope the error
Establish whether the mistake is a single line on a single declaration, every declaration for one product line, or a systemic issue across years of imports. The scope determines the route: a single declaration uses form C2001; multiple historic declarations need a written disclosure to the National Clearance Hub. Pull the entry numbers, MRNs, dates, commodity codes and the declared and corrected values for every affected line.
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2. Calculate underpaid duty, import VAT and interest
Recalculate the customs duty using the correct commodity code, valuation or origin status. Add import VAT on the corrected customs value (unless you account for it through Postponed VAT Accounting). Apply HMRC's published late-payment interest rate from the date the duty was originally due to the date you expect to pay. Show the workings line-by-line — HMRC will ask for them.
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3. Submit the disclosure
For a single in-period adjustment, complete form C2001 and send it through CDS or by post as instructed on the form. For a post-clearance disclosure covering multiple declarations, write to the National Clearance Hub setting out the error, the affected entries, the recalculated liability, the interest, and that the disclosure is unprompted. Keep a dated copy.
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4. Pay the additional duty and VAT
HMRC will issue a C18 post-clearance demand note confirming the amount due. Pay by direct debit, Faster Payments, BACS, CHAPS or cheque using the C18 reference. If you are on Postponed VAT Accounting, the import VAT element is recovered on your VAT return rather than paid with the duty.
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5. Document the disclosure for four years
Regulation 18 of SI 2018/1248 requires you to keep customs records for four years. File the C2001 or disclosure letter, your calculations, the C18 demand, proof of payment, and any HMRC correspondence with the original entry papers. Update your internal customs procedure so the same error does not recur.
Calculate what you owe
The duty rate is the rate that applied on the date of acceptance of the original declaration, not today's rate. Import VAT is charged on the customs value plus duty plus any incidental costs to the first destination in the UK. Interest runs from the original due date — check HMRC's current rate before you submit, as it changes with Bank of England base rate.
What happens next
HMRC normally acknowledges a written disclosure within 30 days. You will receive a C18 demand for the duty, VAT and interest. If a penalty is being charged, HMRC will write separately with the proposed amount and the mitigation given for unprompted disclosure, cooperation and disclosure quality. You have 30 days to request a statutory review or appeal to the First-tier Tribunal (Tax) under section 16 of the Finance Act 1994.
How this connects to your wider obligations
Voluntary disclosure is one half of post-clearance compliance. The other half is preventing the next error: a documented classification process, valuation working papers signed off by someone independent of the buyer, and a quarterly reconciliation of declared values to supplier invoices and royalty agreements. If your disclosure has uncovered a systemic problem, fix the process before HMRC asks how you will.
Tell HMRC about a customs error (CHIEF/CDS amendment guidance)