Migration from CHIEF to CDS — What Changed for Declarants and UK Importers After 2024

Key Differences Between CHIEF and CDS — What Changed in the Declaration Structure

CDS uses a different data format from CHIEF — based on the WCO (World Customs Organization) standard and the European UCC (Union Customs Code Data Requirements) format, adapted by HMRC to the realities of post-Brexit UK. Declaration fields are numbered differently (e.g. field 1/6 instead of Box 1), statistical codes have different structures, and customs procedures (CPC) have been changed and expanded. For declarants working on CHIEF templates — even experienced ones — the transition to CDS required reprogramming declaration systems and retraining staff. Below we describe the changes that most frequently cause errors in practice.

New Mandatory Fields in CDS — What CHIEF Did Not Require

CDS introduced several mandatory fields that CHIEF either did not have or treated as optional. The most important are: field 3/16 (Importer identification number — importer's EORI, mandatory for all import declarations; in CHIEF it could be omitted in some cases), field 4/6 (Statistical value — the statistical value of goods required for imports above certain thresholds), field 5/8 (Country of destination code — mandatory in CDS for many procedures). Missing any of these fields causes automatic rejection of the declaration with an error message. Easy Clearance checks the completeness of all CDS fields before submitting a declaration — which is particularly important for clients coming from other agencies operating on old templates.

CPC Codes in CDS — How They Changed Compared to CHIEF

Customs Procedure Codes (CPC) in CDS use a 7-digit format instead of the 6-digit format used in CHIEF (e.g. 4000000 instead of 40 00 000). Beyond the format, the available codes have also changed: some CHIEF procedures have no direct equivalent in CDS, and some new CDS procedures did not exist in CHIEF. The most common error: using a CHIEF code in a CDS declaration, or vice versa — mapping CPCs without verifying the match. HMRC published an official CHIEF→CDS CPC mapping table in the Communication Pack (gov.uk/guidance/customs-declaration-service-communication-pack). Every customs broker should have an up-to-date CPC mapping — verify this by asking your partner which version of the table they are using.

Duty Repayment (Drawback) and Appeals in CDS vs CHIEF

The customs duty drawback procedure — used when imported goods are subsequently re-exported — is handled differently in CDS. In CHIEF, a duty repayment claim could be submitted via form C285, which directly referenced the CHIEF declaration number. In CDS, duty repayment claims are submitted through the CHIEF Repayment system (for historical CHIEF declarations) or through the new CDS portal for declarations submitted after the migration. Declarants should ensure their duty repayment claim process is aligned with the system in which the original declaration was made. Detailed duty repayment procedure in CDS: gov.uk/guidance/customs-declaration-service. Repayment claims for CHIEF declarations made before the migration are still processed by HMRC but through a separate channel.

Practical Implications of the CDS Migration for UK Importers in 2025–2026

The technical migration was completed in 2024, but its effects are still felt in 2025 and 2026. Importers who have not updated their processes — particularly those who changed their customs agent or declaration software — may still be operating on partially migrated templates. Below we describe three areas where post-migration issues most commonly surface and what to do to eliminate them.

Verifying Declaration Templates After Migration — How to Check Accuracy

The quickest way to check whether your company is operating on correct CDS templates is to submit a test declaration in the HMRC Developer Sandbox environment (available at developer.service.hmrc.gov.uk). Customs agents with CDS access can also validate templates directly before submitting a declaration — CDS returns a validation message listing errors before the declaration reaches the HMRC system. Importers using their own ERP systems connected to CDS via API (rather than through an agent) should verify the field mapping is up to date with their system provider. HMRC regularly updates the CDS API specification — changes are announced at developer.service.hmrc.gov.uk.

DAN (Deferment Account Number) and DDA in CDS — Operational Differences

In CHIEF, the duty deferment account number (DAN) was entered in a specific declaration field. In CDS, the duty deferment mechanism is handled through field 2/6 (Deferred payment), referencing the DDA (Duty Deferment Account) number. The format and method of referencing differ from CHIEF — which is a common source of errors for importers who hold a DDA but whose customs agent enters the data in the old format. Incorrectly entering the DDA number results in an immediate cash payment demand at clearance instead of deferment. Details on DDA in the context of CDS: gov.uk/guidance/duty-deferment-account.

CDS Declaration Statuses — How to Read System Messages

CDS uses a different set of statuses and response messages than CHIEF. Key statuses: 'Accepted' (declaration accepted, MRN assigned — goods can be released), 'Cleared' (declaration and payments verified, procedure completed), 'Rejected' (error in declaration — requires correction), 'Pending' (awaiting data completion or HMRC verification), 'Under Query' (HMRC has questions — contact required). The most important difference from CHIEF: in CDS there is no separate 'E2' (Entry accepted) status — instead there is directly 'Accepted' with an MRN assigned. Knowledge of CDS statuses is essential when monitoring declarations and planning collection of goods from port.

How Easy Clearance Operates in the CDS System — A Practical Guide for Clients

Easy Clearance operates exclusively in CDS — we no longer process any declarations through CHIEF, which is closed. We hold an active CDS account with full authorisation to submit import, export and transit (T1) declarations. Our declaration templates are regularly updated in line with HMRC communications — which means clients coming from other agencies immediately receive an audit of their existing templates and any necessary corrections. Below we describe how working with us looks in practice.

What the Client Must Provide for Easy Clearance to Submit a CDS Declaration

To submit an import declaration in CDS, Easy Clearance requires: a commercial invoice with full seller and buyer details, the importer's EORI number (GB), the HS code for the goods or a description enabling identification, the customs value of the goods (CIF or FOB depending on the procedure), transport documents (CMR, bill of lading or AWB), and the country of origin of the goods (for verification of customs preferences). If the goods are subject to additional controls (sanitary, phytosanitary, veterinary), the relevant certificates or permits are required. Missing any of these elements delays submission of the declaration — which is why we send our clients a document checklist for every clearance.

Customs Clearance Time in CDS — What You Can Expect

CDS is faster than CHIEF for simple Route 1 import declarations (goods released automatically upon acceptance of the declaration). In a typical scenario for road freight: declaration submitted by Easy Clearance 2–4 hours before the vehicle arrives at port, accepted by CDS within 5–30 minutes of submission, GMR generated immediately after the declaration MRN is obtained. Total time from first contact to a ready GMR: typically under 2 hours with complete documentation. Import clearance cost: from £45 to £150. Prices quoted are indicative ranges — exact quote after document review. This article reflects the legal position as at 2026-04-18. Please consult a customs broker before taking action.

What the current rules say

CHIEF was switched off in 2024 — CDS is the only UK customs declaration system, with a data structure and CPC codes completely different from CHIEF. Companies still operating on old templates risk declaration rejection, incorrect duty accounting or DDA problems. Easy Clearance operates exclusively in CDS, offers an audit of existing templates and guarantees declaration completeness in line with current HMRC requirements. Import clearance cost: from £45 to £150 — prices quoted are indicative ranges, exact quote after document review.

FAQ — frequently asked questions

When exactly was CHIEF switched off?

CHIEF for imports was switched off on 30 September 2022. For exports, CHIEF continued operating until March 2024. From March 2024, CDS (Customs Declaration Service) is the only system for submitting UK customs declarations.

Are old declarations submitted in CHIEF still valid?

Yes — historical CHIEF declarations remain valid and are archived by HMRC. Duty repayment claims for CHIEF declarations are submitted through a separate HMRC channel, not through CDS.

What does the difference in CPC codes between CHIEF and CDS mean in practice?

Customs Procedure Codes (CPC) in CDS use a 7-digit format instead of the 6-digit format from CHIEF. The CHIEF→CDS code mapping is available in the Communication Pack at gov.uk/guidance/customs-declaration-service-communication-pack. Using a CHIEF code in a CDS declaration results in a validation error.

How can I check whether my customs agent is using up-to-date CDS templates?

You can ask the agent for the version of the CHIEF→CDS CPC mapping table they are using and the date of the last template update. The agent should also be able to explain which fields changed compared to CHIEF. A lack of clear answers is a signal that it may be worth considering switching agents.

Can a CDS declaration be rejected due to incorrect data format?

Yes. CDS validates the declaration before assigning an MRN and rejects it if any field has an incorrect format, mandatory data is missing or the CPC code is unknown to the system. A rejected declaration requires correction and resubmission — which delays clearance and may result in goods being held at port.

Official sources

• GOV.UK — Use the Customs Declaration Service — GOV.UK / HMRC
• GOV.UK — Customs Declaration Service communication pack — GOV.UK / HMRC
• HMRC CDS API documentation — HMRC
• GOV.UK — Duty Deferment Account in CDS — GOV.UK / HMRC