Customs Compliance · September 2026
A transposed digit in a Commodity Code is still a valid code. A wrong EORI, if it belongs to a real company, clears just as cleanly as the right one. Neither error stops a consignment at the border. Both keep repeating, quietly, until HMRC opens a compliance check and works back through three years of entries. That is when a small mistake becomes a very large number. Knowing how to check a customs declaration, and which fields to check first, is what stops it getting that far.
This guide sets out what to check on a customs declaration, why the responsibility for getting it right sits with you rather than your agent, and what it costs if you don't check.
Settle this before anything else, because many businesses get it wrong. If you are named as the Importer, the declaration's accuracy is your legal responsibility, not your agent's.
They act in your name, and you carry the Customs Debt alone.
They are jointly and severally liable alongside you — and HMRC can still come to you first.
The tribunals have been consistent on this. Responsibility for a correct declaration sits with the business, whether or not a representative is used. You may have commercial recourse against an agent who makes a keying error, so check your terms of engagement. But your money goes to HMRC first. You argue about it afterwards.
HMRC can go back three years from the date the Customs Debt was incurred, longer where evasion is suspected. Nobody gets assessed on the single entry that troubled them. They get assessed on every entry that repeated the same error. A £600 shortfall on one consignment is nothing. The same shortfall across three years of monthly shipments, with import VAT on top, is a conversation with your finance director.
Under Notice 301, contraventions attract up to £2,500 for the more serious irregularities and £1,000 for others. HMRC's approach favours education first: a penalty won't usually follow unless a warning letter for a similar issue was already issued in the past two years.
A first contravention can still attract a penalty if the error is serious, if you ignored written instructions HMRC had already given you, or if a C18 has been issued for a Customs Debt of £10,000 or more — a threshold most businesses assume is higher than it actually is.
Once your entries draw attention, your consignments get selected more often and your lead times suffer. If you hold AEO status, a Special Procedure authorisation, or a deferment guarantee, your compliance history is exactly what gets reviewed. Goods can be seized outright: a tribunal upheld a refusal to restore goods where an importer had taken Commodity Codes from a third-party website, passed them to their agent, and never checked them.
On the export side, your declaration is your proof the goods left the UK. If it's wrong or missing, your VAT zero-rating is exposed — and that means an assessment on the full value of the sale rather than a duty difference.
Finding your own mistake and reporting it is the cheapest outcome available to you. Sitting on it is what gets expensive.
You can't check a declaration in isolation. You're comparing it to something. Before you start, gather the following.
Everything you need in front of you before you open the entry.
If you can't produce these, the checking problem is the smaller of your two problems. You're required to keep supporting records for at least three years, longer where an assessment or appeal is running.
Almost nobody knows all the codes from memory, so the trick is knowing which reference answers which question.
The UK Integrated Online Tariff is where you check the goods themselves. Search the Commodity Code and it tells you what the code covers, the duty rate, and every other measure attached to it. Add the country of origin and you'll also see the preferential rate, whether Anti-Dumping or Countervailing Duty applies to goods from that origin, any tariff quota, and any licence requirement. Checking the rate on its own isn't checking the code properly.
Volume 3 for CDS holds the completion instructions data element by data element, plus the appendices listing valid codes. There are separate collections for imports and exports. The appendices you'll use most:
Three things worth knowing before you open it. Volume 3 is split by movement type, and each has its own appendices, so checking an import entry against the export appendix sends you confidently to the wrong answer. Where Appendix 1 or 2 gives a different rule from the main guidance, the appendix takes precedence, so read the procedure code's own rules first. And Volume 3 changes between publications, announced through Tariff Stop Press notices — subscribe to the alerts if you want to know when a rule changes.
The full data set runs to well over sixty Data Elements. These are the ones where an error costs money or puts the liability in the wrong place.
Importer EORI (DE 3/16). Read it digit by digit, including the three-digit suffix. Group companies sharing a VAT registration often have EORIs with the same root, differing only by that suffix, so they look identical at a glance. The Customs Debt attaches to the EORI — not to the name printed underneath it, not to who paid the supplier, and not to who owns the goods.
Representative status (DE 3/21). Check it matches how you actually appointed your agent, direct or indirect. It decides who's liable alongside you.
Commodity Code (DE 6/14 to 6/17). Two separate questions, needing two separate sources. Is it the code you instructed? Compare against your clearance instruction, reading the digits individually rather than scanning the number as a shape; a transposed code is usually still a valid one, so nothing flags it. Is that code still correct? Check it in the Online Tariff. Codes change, explanatory notes get published, rulings expire, and an expired ruling protects you from nothing. Look past the duty rate at the measures underneath it: Anti-Dumping Duty is origin-specific, so the same code can be harmless for one supplier and expensive for another.
Description of goods (DE 6/8). Specific enough that someone who has never seen the goods could classify them from it. "Parts" and "goods as per invoice" aren't descriptions, and a vague one often draws an officer's attention in the first place.
Country of Origin (DE 5/15). Where the goods originate, not where they were shipped from. Goods don't acquire the origin of a country they merely pass through. This is the single most common area of post-clearance recovery.
Preference (DE 4/17). The preference code claims the preferential rate, with the supporting document declared in DE 2/3. Check both against the proof of origin you actually hold. Claiming preference without valid proof carries three years of retrospective exposure.
Additions and deductions (DE 4/9). Where money quietly leaks. Freight and insurance to the UK border, packing, tooling supplied free to the manufacturer, royalties, and separately invoiced charges commonly belong in the Customs Value and commonly get left out. It runs the other way too: duty paid on UK-leg transport is duty overpaid.
Invoice currency (DE 4/10). The classic error is a sterling invoice keyed as dollars and converted, under-declaring the value on every entry until someone notices.
Procedure and Additional Procedure Codes (DE 1/10 and 1/11). Check against your authorisation and your instruction. Claiming a procedure you're not authorised for is a serious contravention. Paying full duty on goods that should have gone into a Special Procedure is money given away.
Documents produced (DE 2/3). If a licence, certificate or preference document code is quoted, the document itself needs to be in your records.
Additional fiscal references (DE 3/40). Using Postponed VAT Accounting? Check FR1 and your VAT number are both there, or you've paid import VAT at the border you didn't mean to pay.
Our How to Check a Customs Declaration course is a practical 90-minute session built around real import and export entries. We take a full entry printout apart field by field and show you exactly where the errors hide.
The fix depends on two things: whether the goods have cleared, and whether you've underpaid or overpaid. There's no single form for 'fix my entry'.
If the declaration has been submitted but the goods haven't been released, it can still be amended. Tell your agent immediately. This is by far the cheapest point to fix anything, which is an argument for checking entries as they happen rather than in a monthly sweep.
Once an import declaration has cleared, it can't be amended in CDS. You make a voluntary disclosure instead, through HMRC's voluntary clearance amendment service — the old postal C2001-CDS form was withdrawn in May 2025. You'll need the MRN, the goods item number, the Data Element you got wrong, what it was entered as, what it should have been, and supporting documents. HMRC will then issue a C18 Post Clearance Demand Note for the additional duty or VAT.
One exception. If you used Postponed VAT Accounting (FR1 in DE 3/40) on the original entry, don't use this service to correct underpaid import VAT. Account for it on your VAT Return instead. That holds even if PVA was selected in error.
Overpayments are claimed back through HMRC's repayment service. If you hold an EORI and the declaration was made on CDS, you claim in the Customs Declaration Service itself; the online C285 form covers the cases that fall outside that, such as claims by private individuals or those without an EORI. You can no longer claim by post for declarations made on CDS.
The time limits are worth memorising: three years for overpayments, one year for rejected imports, and 90 days for withdrawal of an import declaration. And a trap that catches people out: if you're VAT registered, you can't reclaim overpaid import VAT this way at all. Adjust it through your VAT Return instead. The repayment claim is for the duty only.
Correcting an error isn't an admission that costs you extra. HMRC won't normally charge a civil penalty where a business discovers and voluntarily discloses a contravention itself. Finding your own mistake is the cheapest outcome available.
None of this is difficult once you know which fields matter. The difficulty is that checking declarations sits in nobody's job description until the day it matters.
Four habits, none of them onerous, that catch almost everything.
Not as far as HMRC is concerned. If you are named as the Importer, the accuracy of the declaration is your legal responsibility. You may have commercial recourse against the agent under your terms of engagement, but HMRC assesses you first and you recover afterwards.
No. Once an import declaration has cleared, it can't be amended in CDS. If you underpaid, you make a voluntary disclosure and HMRC issues a C18. If you overpaid, you make a repayment claim. Only declarations submitted but not yet released can still be amended directly.
Three years from the date the Customs Debt was incurred, and longer where evasion is suspected. The exposure is rarely one entry — it's every entry that repeated the same error across that period, with import VAT on top.
The Commodity Code and the Importer EORI, on every single entry, compared against your clearance instruction. Between them they decide what you pay and who owes it, and both can be wrong while still looking perfectly valid. Everything else can go into a monthly sample.
Not if you're VAT registered. Overpaid import VAT is adjusted through your VAT Return, by reducing the output tax due in Box 1 and keeping records to support it. The repayment claim covers the duty only.
If your team receives copies of entries from a customs agent and files them without reading them, this is worth an hour of your time. In this practical 90-minute live online session we work through a full entry printout field by field, show you where the errors hide, and cover how to put a mistake right once you've found one — including how to navigate the Tariff to confirm a code and what your options are for correcting a declaration after clearance. It's aimed at Export and Import Office teams: the people who receive the paperwork and are expected to do something sensible with it.
Next date: 13 October 2026.
Price: £105 + VAT per delegate.
Our upcoming Preparing for a Customs Audit course covers similar ground from the audit side, with details following on the website shortly. If you'd like to talk through how your business checks its declarations, or would prefer this session delivered in-house using your own entries, get in touch. We're always happy to help.
Tariff Classification · September 2026 The Tariff Code Question That Determines Whether You Overpay or Underpay Duty Many commodity codes are chosen once and never
Customs Compliance · September 2026 How to Check a Customs Declaration: A Practical Guide A transposed digit in a Commodity Code is still a valid
Whether you need immediate help with a trade issue, want to strengthen your internal processes or are looking for the right training or service, we can point you in the right direction.
