Three Identifiers, One Identity
UK customs access runs on three identifiers that beginners constantly confuse. Think of them as a small schema: the Government Gateway account is your login credential, the Unique Taxpayer Reference is your tax identity, and the GB EORI is your trading identity. CDS registration is the join operation that links all three.
How the Identifiers Map
The relationships are strict. Your Gateway account authenticates you to government services. Your UTR, a 10-digit number issued to every registered taxpayer and company, proves the business behind the login. Your EORI, formatted as GB plus 12 digits, is how customs systems recognise you on every declaration. Notably, there is no fourth identifier: no separate CDS registration number exists, because the EORI fills that role. The full mapping, with application routes for each, sits in this guide to registering for the Customs Declaration Service.
Deriving the EORI
For VAT-registered businesses the EORI is usually deterministic: the 9-digit VAT number wrapped with GB at the front and 000 at the end, so 123456789 becomes GB123456789000.
Edge Case: Northern Ireland
Movements involving Northern Ireland can require an XI EORI alongside the GB one, and the XI application only succeeds once the GB record is active. Dependency order matters everywhere in this system.
Identity sorted? The filing layer is next. iCDS submits UK import declarations in around three minutes. Watch a demo
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