EXPP5270 - Customs Handling of Import and Export Freight (CHIEF) export declarations: Declaration Unique Consignment Reference (DUCR)
Source: gov.uk (2025-11-24)


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A DUCR is a 35 character reference (plus an optional 4 character suffix - made up of 3 numerical 'part' identity and a check letter) allocated by a trader to a consignment of goods and recorded on the relevant customs declaration(s). Once recorded on CHIEF, DUCRs may not subsequently be amended.

Use of DUCRs

DUCRS must be included on all Pre Shipment Advices (PSAs), supplementary declarations and full declarations submitted by traders authorised for simplified procedures. The same Declaration UCR recorded on a PSA must also be recorded on the linked supplementary declaration(s) and provide an audit trail into the authorised trader's records.

Where there is more than one supplementary declaration per PSA the DUCR (part) field is to be used to make the DUCR unique for each shipment under the PSA.

The standard format of DUCRs to be used in the National Export System is based on the latest recommended World Customs Organisation draft ie up to 35 characters in length in 4 parts as follows:
- 1st part = The year in which the UCR was allocated for example '9' if allocated in 2009
- 2nd part = The country where the UCR was allocated. Typically 'GB' for UK export declarations
- 3rd part = The identity of the (authorised) trader as known to Customs. In the UK this will be the Economic Operator Reference and Information (EORI), followed by a hyphen '-'
- 4th part = A unique (within a trader's system) series of characters which a trader devises and which provides an audit trail within their commercial accounting systems. This part of the UCR is restricted to numbers, upper case letters and certain special characters namely '0' to '9', 'A' to 'Z', or a hyphen '-'.
An example of a Declaration UCR based on the above is: '9GB123456789012-ABC1234'. The field is left aligned and trailing spaces are ignored, that is no trailing characters such as '0' are added so its size is variable.

Note: DUCRs have been implemented on CHIEF so that when future Customs freight initiatives which also make use of World Customs Organisation (WCO) UCR standards are introduced, they will be compatible with the NES eg a non UK UCR could be quoted on NES declaration.

There is a further optional field of 4 characters which is available. This allows several export declarations to have the same core Declaration UCR. It also provides a check letter calculation facility for the trade (to guard against any mis- keying). It is this, in combination with the (up to) 35 character UCR which must be unique.

The first 3 spaces in this field can contain up to 3 numeric 'part' number. The fourth space in this field can contain an optional check letter. CHIEF does not insist that a check letter is supplied, but if one is input then it is checked and the UCR part rejected if found to be invalid.

Whenever CHIEF shows a part number in a message or on a printed report or on a screen, the check letter is included. However, neither the 3 numeric part number nor the alpha check letter need be supplied as they are entirely optional the part number defaults to null (spaces) on CHIEF if not used. Whether or not supplied, CHIEF will calculate and advise the check letter - if not required it can therefore be ignored.

CHIEF ensures that the Declaration UCR is unique amongst all known DUCRs and MUCRs and establishes it together with any part number as a key to a Unique export declaration. The only exception to this rule is where the same DUCR (part) must be quoted on both a Pre Shipment Advice (PSA) and the related supplementary declaration.