How to Complete and Submit Form C88: CDS Filing, Duty, and Records

To complete and submit Form C88, the UK customs declaration also known as the Single Administrative Document (SAD), you register for an EORI number and the Customs Declaration Service, classify every item under a UK Trade Tariff commodity code, enter the required data elements electronically through CDS with a commercial invoice and transport document attached, and settle any duty and import VAT before HMRC releases the goods. Paper C88 forms are no longer accepted for standard declarations; since 4 June 2024 all import and export declarations run through CDS.¹

When a C88 Is Actually Required

A C88 declaration is required for any commercial goods entering or leaving the United Kingdom, and for non-UK goods transiting the country under a transit procedure.² The obligation sits with the importer or exporter of record, even where a customs agent files on their behalf.

Private individuals moving personal belongings or small purchases within duty-free allowances generally don’t need to file one. Commercial imports valued below £135 currently use a simplified low-value goods process instead of a full declaration, though that threshold is scheduled to change by 2029. Bringing alcohol, tobacco, or other excise goods above personal-use limits still triggers a declaration for the excise duty.

Check your Incoterms before the shipment moves. Under Delivered Duty Paid (DDP) the seller handles clearance and pays import duties and VAT. Under Delivered at Place (DAP) the buyer does. Get this settled in the contract so the right party is set up to file.

Set Up Before You File

Get an EORI Number

Every business or individual making UK customs declarations needs an Economic Operators Registration and Identification number. GB EORI numbers begin “GB” followed by 12 digits. You apply through GOV.UK, and you’ll need your Unique Taxpayer Reference, business start date, Standard Industrial Classification code, and your VAT number if you’re VAT-registered. Sole traders and individuals also give their National Insurance number.³

Most applicants get their GB EORI back immediately, though HMRC checks can take up to five working days. If your goods movements involve Northern Ireland, you’ll also need an XI EORI, which requires the GB number first plus proof of a permanent business establishment in Northern Ireland.³

Subscribe to CDS

With the EORI in hand, subscribe to the Customs Declaration Service. Sign in with Government Gateway credentials and supply your EORI, UTR, the business address HMRC holds on its customs records, and (for individuals or sole traders) your National Insurance number. Access is usually granted within two hours, sometimes up to five working days.⁴ You cannot subscribe using an agent’s Government Gateway ID; it must be your own business credentials.

Find the Right Commodity Code

Every item in your shipment needs a commodity code from the UK Integrated Tariff. The code sets the duty rate, the VAT rate, and any licence or certificate requirements. Look it up at gov.uk/trade-tariff. To classify accurately you need to know the product type, its use, what it’s made from, how it’s produced, and how it’s packaged.⁵ The tool includes an A-to-Z index of classified goods as a starting point.

Wrong codes are one of the most common reasons declarations run into trouble. An incorrect code means paying too much duty, paying too little (which triggers penalties later), or missing a required import licence.

The Data Elements You Have to Get Right

CDS uses numbered “data elements” rather than paper boxes, but the information maps to the original C88 layout. The fields where errors are most costly are these:

DE 1/1 (Box 1) — Declaration type. Identifies whether you’re filing an import, export, or transit declaration and the procedure category. The letters you enter (such as “IM” for import or “EX” for export) control which other fields the system expects.⁶
DE 1/10 (Box 37) — Procedure code. A four-digit code for what you’re doing with the goods. Common codes include 40 (release to free circulation), 51 (inward processing), 53 (temporary admission), and 71 (entry to a customs warehouse). The wrong procedure code can accidentally lock goods into the wrong regime.⁷
DE 3/16 (Box 8) — Consignee. Full name, address, and EORI number of the person or business receiving the goods.
DE 6/8 (Box 31) — Description of goods. Plain-language description, number and type of packages, and any marks or container numbers.⁶
DE 6/14 (Box 33) — Commodity code. The tariff classification code for each item line.
DE 4/4 (Box 46) — Statistical value. Transaction value of the goods, normally including insurance and freight up to the UK border for imports.

Valuation must reflect the price actually paid or payable, plus insurance and freight. Undervaluing to reduce duty is treated as a serious contravention, and the penalty scale escalates quickly on large underdeclarations.

Bringing goods in temporarily, say for a trade exhibition or samples for testing? Procedure code 5300 lets you avoid import duties provided the goods leave again within the allowed time. The importer must hold the temporary admission authorisation and declare an additional procedure code specifying the type of relief.⁸

Documents That Have to Sit Behind the Declaration

CDS won’t process a declaration without the underlying paperwork. At a minimum:

Commercial invoice showing seller, buyer, description, price, and currency. It proves the transaction value and origin.⁹
Packing list breaking down what’s in each package or container, with weights and dimensions. Officers use this on physical inspection.
Transport document: a Bill of Lading (sea), Air Waybill (air), or CMR note (road) establishing legal custody in transit.

Depending on the goods, you may also need certificates of origin, import licences, phytosanitary certificates, or other regulatory paperwork. The Trade Tariff tool flags these when you look up a commodity code, so checking before you ship is far less painful than finding a missing licence at the border.

Submitting the Declaration Through CDS

All UK declarations now go through the Customs Declaration Service. The older CHIEF system was phased out (imports in September 2022, exports on 4 June 2024).¹⁰ Paper C88 forms are not accepted for standard declarations.

Most traders use customs software or an agent to transmit into CDS. The system validates data against HMRC databases in real time and either accepts or rejects the submission. HMRC publishes the full list of CDS error codes so you can diagnose the exact reason for a rejection and correct it.11 Common rejections involve mismatched EORI numbers, invalid commodity codes, and missing data elements that the chosen procedure code requires.

Paying Duty and VAT

Once CDS accepts the declaration, any duty and import VAT must be settled before goods are released. CDS offers several methods:

Immediate payment by debit card using a CDSI reference number generated by the system.
Cash account. Every CDS subscriber gets one automatically. Pre-fund it by bank transfer and linked declarations clear immediately; payments typically credit within two hours.
Duty deferment account (DDA). Defer duty and settle monthly by direct debit. This is the standard option for regular importers, topped up via Faster Payments, CHAPS, or Bacs.
General guarantee for disputed or estimated amounts. HMRC issues a guarantee reference, and the amount is reconciled once the final liability is confirmed.

Under DDP Incoterms, the seller (or their UK agent) still needs a funded CDS payment method. CDS does not release goods until the financial obligation clears.

Clearance Timings

After CDS accepts the declaration and payment clears, HMRC issues a clearance notification. For air freight, road freight, and roll-on-roll-off imports, goods are typically cleared within two hours of HMRC receiving any requested supporting documents. Marine freight clears within three hours if documents are submitted between 8am and 3pm, or by 8am the following day if submitted later.¹²

Delays usually come from HMRC flagging a shipment for a document check or physical inspection. Fast responses to document requests keep the clock in your favour. Physical inspections add more time and are more common for controlled items, high-risk origins, or declarations with discrepancies.

Fixing Errors After Clearance

Mistakes found after release aren’t fatal, but they have deadlines. If you overpaid duty or import VAT because of a declaration error, you can claim a repayment within three years. For CDS declarations you apply through the CDS online service using your EORI and the declaration’s Movement Reference Number (MRN).¹³

Private individuals without an EORI, non-VAT-registered importers reclaiming import VAT, and certain Northern Ireland claims use the C285 form instead. VAT-registered businesses cannot use either route for import VAT overpayments; they adjust the VAT return by reducing output tax in Box 1 and keep records to support the correction.¹³

Rejected imports have a shorter one-year window for repayment claims, and withdrawing a declaration entirely has to happen within 90 days.

If You Use a Customs Agent

Many businesses hire a customs agent, freight forwarder, or broker to file for them. The agent must be established in the UK for customs purposes. Before they can act, you provide written authorisation stating whether they represent you directly (declarations in your name, on your account) or indirectly (declarations in the agent’s name, on your account).¹⁴

The point that catches people out: appointing an agent doesn’t transfer your legal responsibility. You remain accountable for accuracy. If the agent enters the wrong commodity code because your product description was vague, the penalty lands on you. Keep the written agreement, and give the agent accurate invoices, packing lists, and product details for every shipment.¹⁴

Records You Must Keep

UK customs traders must keep declarations and supporting documents (invoices, transport documents, packing lists, correspondence with agents, and copies of the declarations themselves) for four years from the date the obligation to preserve them arises.¹⁵ HMRC can request them at any point within that window during a compliance check, and failure to produce them can bring a financial penalty.¹⁶ Digital storage is fine, provided you can pull up a specific shipment quickly.

What Errors Cost

HMRC applies civil penalties on a sliding scale. The minimum is £250 for a first offence, rising with repeated similar contraventions: £250, then £500, then £1,000. For more serious irregularities the progression continues to £2,000 and up to £2,500 per contravention.¹⁷

HMRC can skip the normal progression for significant underpayments. If undeclared duty or import VAT exceeds £50,000, the starting penalty jumps two steps higher than normal. Above £100,000, HMRC may charge the maximum penalty even on a first offence.¹⁷ Errors that affect HMRC’s physical control of goods, such as removing items from a customs-controlled area before clearance, have no monetary threshold for being treated as serious.

1
GOV.UK. NTE 2024/12: Export Declarations Move From CHIEF to CDS From 4 June 2024
2
European Commission. Single Administrative Document
3
GOV.UK. Apply for an EORI Number
4
GOV.UK. Subscribe to the Customs Declaration Service
5
GOV.UK. Trade Tariff: Look Up Commodity Codes, Duty and VAT Rates
6
HM Revenue and Customs. C88 Customs Declaration Form
7
GOV.UK. Appendix 1: DE 1/10 Requested and Previous Procedure Codes
8
GOV.UK. Requested Procedure 53: Entry to Temporary Admission
9
GOV.UK. Making a Full Export Declaration
10
GOV.UK. NTE 2024/12: Export Declarations Move From CHIEF to CDS From 4 June 2024a>
11
GOV.UK. Customs Declaration Service Error Codes
12
GOV.UK. Clearing Goods Entering, Leaving or Transiting the UK
13
GOV.UK. How to Claim a Repayment of Import Duty and VAT if You’ve Overpaid
14
GOV.UK. Get Someone to Deal With Customs for You
15
Legislation.gov.uk. The Customs Traders (Accounts and Records) Regulations 1995
16
GOV.UK. Compliance Checks: Customs and International Trade — CC/FS1g
17
GOV.UK. Civil Penalties for Contraventions of Customs Law (Customs Notice 301)