Making an import supplementary declaration

Last updated 19 April 2024

You’ll need to make a supplementary declaration after you’ve either made:

• an entry in your own declarations
• a simplified frontier declaration

Who can submit

If you move goods into Great Britain (England, Scotland and Wales), you may be able to declare them without getting authorisation in advance. You can do this by entering them in your records and making supplementary declarations. You can do this up to 175 days after the date you imported the goods.

This applies if you brought goods: 

• from free circulation in Ireland (including goods that started their movement in Northern Ireland) into free circulation in Great Britain, on or before 30 January 2024 
• that need to be declared from Northern Ireland (including goods that started their movement in Ireland) into free circulation in Great Britain, on or before 30 January 2024

You will not be able to do this for controlled or excise goods.

When to submit

You will not need to submit a supplementary declaration when your goods are being declared to customs warehousing.

You can submit your supplementary declaration after any of the following:

• your simplified frontier declaration has been accepted
• your C21 (customs clearance request) has been accepted
• you’ve made an entry in your records

Your supplementary declaration must then be sent and accepted by the 10th calendar day of the following month.

How to submit

You can submit your declaration electronically to HMRC.

Your declaration will need to include the:

• customs procedure code

• commodity code

• declaration unique consignment reference which is the main reference number that links declarations

You also need to give the:

• consignee and consignor

• type, amount and packaging of your goods

• transport methods and costs

• currencies and valuation methods

• certificates and licences

You must check which data elements you need to complete on your declaration, using the Customs Declaration Service.

You can submit declarations individually, or in batches. You can also submit more than one supplementary declaration for a single, simplified declaration.

You can submit less supplementary declarations by combining those with the same header and item level data, into a single declaration. This is called aggregation. You must get approval from your authorising customs officer before you do this.

After you submit

Once your supplementary declaration is accepted, you will be sent a customs response message, giving a calculation of what you owe. Payment will be taken from your deferment account on the 16th calendar day of the following month.

You also need to submit a final supplementary declaration.

You may be asked to send supporting documents for a customs check to clear your goods. Find out about clearing goods entering, leaving or transiting the UK.

Find out what to do if you have missed the deadline for submitting your supplementary declaration.

Amend or cancel a declaration

Find out what to do if you need to amend or cancel a declaration.

If you do not pay the right amount

Find out what to do if you underpay import or export duties and who is responsible for the debt.

If you have overpaid customs duty, you can apply for a refund. Find out about refunds and waivers on customs debt by HMRC.