CDS customs declaration – how to read a UK customs entry and what each box means

Every importer into the United Kingdom receives a copy of the customs declaration from their customs broker after clearance — most often in the form of an Entry Acceptance or a C88 document (customs entry acceptance). The problem is that this document, filled with four-digit codes, abbreviations and dozens of numbered boxes, is completely unreadable for most importers. Yet it is precisely in this document that the key information is hidden: what duty was charged and why, which HS code the customs agent applied, whether a tariff preference was claimed, and what the MRN reference number is for tracking the status of the consignment. CDS (Customs Declaration Service) is HMRC's IT system that replaced the old CHIEF system in 2023. Understanding the structure of a CDS declaration is not merely an academic exercise — it is a real capability to verify your agent's work, check that duty has been calculated correctly, and react quickly when something goes wrong. In this article we explain step by step how to read every important box of a customs declaration in the CDS system — in plain language for an importer, not a customs officer.

CDS vs CHIEF — why the system changed

Until November 2023 the UK processed customs declarations through the CHIEF system (Customs Handling of Import and Export Freight). CDS (Customs Declaration Service) is its successor — a modern platform built on European UCC (Union Customs Code) standards, although the UK post-Brexit implemented its own version based on the UK Global Tariff.

For an importer, the switch from CHIEF to CDS means: - Declaration formats and boxes have changed - The MRN (Movement Reference Number) now has a different format - The process for amending declarations (correcting errors) is different - Importer access to declaration history is via the CDS portal (gov.uk)

If you have older customs documents from before 2023 — they may look slightly different. The guide below covers the current CDS format.

Structure of a customs declaration — general overview

A CDS customs declaration is based on a concept similar to the SAD (Single Administrative Document) — the document used throughout Europe. It consists of:

• The declaration header — general data: importer, customs agent, means of transport, port of entry, total value
• Goods items — each HS code is a separate item with its own duty calculation

The C88 document (Entry Acceptance) is a printout from the CDS system confirming that the declaration has been accepted and setting out the charges due. This is the document importers receive after clearance.

Key CDS declaration boxes — explained

Box 1 — Declaration Type

This consists of two parts: - First letter: H = import, E = export, X = re-export - Second letter/digit: A = standard declaration, B = simplified, F = full supplementary declaration

Example: IM A = standard import declaration. Most importers will see exactly this code.

Box 8 — Importer (Consignee / Declarant)

The importer's EORI number in the format GB + 12 digits (e.g. GB123456789000). This box verifies that the customs agent has used the company's correct EORI number. An error in the EORI can lead to problems with import VAT and the ability to reclaim it.

Box 14 — Customs agent (Declarant / Agent)

The customs agent's EORI number. This confirms who lodged the declaration. In the UK a customs agent may act as: - Direct Representative — acts on behalf of the importer; the importer bears liability - Indirect Representative — the agent is jointly and severally liable with the importer for customs debt

Most customs agents in the UK act as Direct Representatives.

Box 22 — Currency and invoice value

Format: ISO currency code + value (e.g. PLN 45000.00). This is the commercial invoice value — the starting point for calculating the customs value.

Important: Customs value ≠ invoice value. The customs value includes the cost of transport and insurance to the UK border (under CIF or equivalent Incoterms). Under EXW or FOB Incoterms, the customs agent adds the cost of sea/air/road freight and insurance.

Box 33 — HS code (Commodity Code)

This is one of the most important boxes — an eight-digit tariff code (UK Commodity Code). The UK uses 10-digit codes (HS + CN + national extension), but in the CDS system Box 33 typically shows 8 digits.

How to verify the HS code: 1. Go to trade-tariff.service.gov.uk 2. Enter the code from Box 33 3. Check the goods description, duty rate and preference conditions 4. Compare with your goods description

If the HS code does not match your goods — this may be an error by the customs agent requiring correction or a voluntary disclosure.

Box 36 — Tariff Preference

A code indicating whether a preferential duty rate has been applied: - 100 = no preference (MFN rate — Most Favoured Nation, i.e. the standard UK Global Tariff rate) - 300 = preference under a trade agreement (e.g. TCA with the EU — Trade and Cooperation Agreement) - 400 = autonomous preference (e.g. for GSP countries — Generalised Scheme of Preferences)

If you are importing goods of Polish (EU) origin and you see code 100 in Box 36 instead of 300 — this means the customs agent has not applied the TCA preference. This may have been due to a missing proof of origin document or an agent error. In that case you can submit a C285 claim for a refund of overpaid duty.

Box 37 — Customs Procedure Code

This is a four-digit code (plus an optional two-digit additional code) indicating the customs procedure applied to the goods. The first two digits are the requested procedure (what happens to the goods after clearance); the next two are the previous procedure (where the goods come from — what customs status they held).

The most important procedure codes for imports:

Code	Procedure
40 00	Release for Free Circulation — goods are imported from a third country and enter the UK market
42 00	Release for Free Circulation with VAT relief (Regime 42 analogue)
61 00	Re-importation (goods previously exported from the UK, returning)
51 00	Suspensive procedure (Inward Processing Relief)
53 00	Temporary Admission (Temporary Admission / ATA Carnet analogue)
71 00	Customs Warehouse — goods under customs supervision

Example: You are importing furniture from Poland to the UK. The procedure code should be 40 00 (release for free circulation). If you see 51 00 — something has gone wrong; the goods are under inward processing instead of standard import.

Box 41 — Supplementary Unit

Some HS codes require an additional unit of measure alongside weight (e.g. for alcohol — litres of pure alcohol; for medicines — DDD doses; for electronics — pieces). Box 41 contains the quantity in that unit. If the customs agent has entered an incorrect quantity — this may affect the accuracy of any excise duty or special charges calculated.

Box 44 — Documents Produced

A list of all documents attached to the customs declaration, in the format: document code + reference number.

Example document codes: - C600 = EUR.1 certificate or invoice statement confirming EU origin (for TCA) - N380 = Import licence - 9104 = Transport document (CMR, BL, AWB) - Y900 = Customs value declaration

If you claimed a tariff preference (Box 36 = 300) but do not see code C600 in Box 44 — this is a red flag. It means the tariff preference is not supported by a document, which could result in HMRC withdrawing it.

Box 47 — Tax Lines (duty and tax calculation)

This is the most important box for an importer from a financial perspective. It contains a breakdown of all charges due:

Column	Description
Tax Type	Type of charge: A00 = standard duty; B00 = import VAT; A20 = anti-dumping duty
Tax Base	The taxable base (customs value for duty; customs value + duty for VAT)
Rate	Percentage rate
Amount	Amount in GBP
Method of Payment	Payment method: E = Duty Deferment Account; A = cash/bank transfer

How to check whether duty is correct: 1. Take the value from Box 22 (invoice value) 2. Add transport and insurance costs to the UK border (CIF value) 3. This is the customs value 4. Multiply by the duty rate for the HS code in Box 33 5. Compare with the A00 amount in Box 47

If the figures do not match — check whether the customs value in the declaration is correct and consult your customs agent.

MRN — where to find it and what it is used for

The MRN (Movement Reference Number) is the unique identifier for each customs declaration in the CDS system. The UK format is 18 characters (e.g. 26GB123456789ABCDE5). Where to find it:

• On the Entry Acceptance document (C88) — usually in the header or top right-hand corner
• In the confirmation from your customs agent (email with the MRN)
• In the CDS portal (for importers registered in the system)

What the MRN is used for: - Tracking clearance status in the CDS system - Reference when contacting HMRC - Reference number in correspondence relating to that declaration - Basis for submitting an amendment or a C285 claim (duty repayment)

How to check the status of a declaration in CDS

Importers registered in the Customs Declaration Service (via Government Gateway) can check the status of their declarations online. The status can be:

Status	Meaning
Accepted	Declaration accepted by the system; goods may be released
Cleared	Clearance complete; goods released
Held	Declaration on hold — awaiting documents or an HMRC decision
Rejected	Declaration rejected — data error; must be corrected and resubmitted
Invalidated	Declaration cancelled (by the customs agent or HMRC)

How to correct an error in CDS after clearance — amendment vs re-declaration

After clearance is complete, the importer or customs agent may identify an error in the declaration. Depending on the nature of the error:

Amendment

For minor formal errors — a typo in the description, an incorrect quantity in Box 41, a missing document reference in Box 44. An amendment is submitted by the customs agent through the CDS system. It can be submitted up to 3 years from the date of clearance.

Important: An amendment that results in additional duty (e.g. correcting the HS code to one with a higher rate) is in effect a voluntary disclosure — HMRC may charge interest on the difference, but in cases of good faith it will not impose a penalty.

Re-declaration

Where the error is so serious that it cannot be corrected by amendment — the customs agent submits a new declaration. This involves the cancellation of the previous one and may require agreement with HMRC.