LRN (Local Reference Number) is a declarant's own reference number, assigned to a customs declaration before it is submitted to the CDS system. The number must be unique and makes it possible to link the declaration to the transport documents and the invoice, before CDS issues the official MRN number once the declaration is accepted. In communication with the carrier and the customs agency, the LRN acts as a temporary case identifier.
Contents
In brief — what you'll learn
- ✓ How to prepare the process and documents
- ✓ How the declaration and control work
- ✓ How to maintain compliance and settlements
How to prepare the process and documents
Division of responsibility between the parties
The minimum data set for the declaration
Easy Clearance is an experienced UK customs broker.
How the declaration and control work
The customs declaration process runs in stages, and each of them generates data required to correctly complete the formalities. Consistency between the commercial documents and the transport data is essential — any discrepancy can result in the cargo being held or the declaration needing to be corrected.
Operational stages from advance notice to release
The most common risk points and how to limit them
How to maintain compliance and settlements
Record-keeping, corrections and evidence of due diligence
Working with a customs agency and internal audit allows companies to keep up to date with regulatory changes, delegate responsibility for the completeness of the data, and shorten clearance times. A quarterly internal audit should verify the correctness of the classification, the settlement of import VAT, and the division of duties between the importer, the exporter and the customs representative responsible for assigning the LRN.
Working with a customs agency and internal audit
Summary
In summary: on the topic of 'What is an LRN?' the most important thing is to run the process according to current official guidance, with a clear division of responsibility and documentation of every decision. This approach reduces delays, cuts the number of corrections and makes it easier to defend the settlements during an audit. If any requirement raises doubts, check the current GOV.UK or KAS guidance before filing a declaration — and for complex procedures, consult a customs agency holding AEO status.
Legal basis and sources
- EC TAXUD: EU Customs Tariff TARIC
- EC TAXUD: EU EORI validation
- KAS: Krajowa Administracja Skarbowa (Polish National Revenue Administration)
If the regulations or system notices are updated, check the current GOV.UK or KAS guidance before submitting a declaration.
Frequently asked questions
What is an LRN and what is it used for in a customs procedure?
The LRN (Local Reference Number) is a unique reference number assigned by the declarant to every customs declaration filed with the HMRC systems. It is used to identify a specific declaration and link it to the commercial and transport documents. Without a correctly assigned LRN, a declaration will not be accepted into the customs system.
Who assigns the LRN — the declarant or the customs office?
The LRN is assigned by the declarant themselves — the importer, exporter or customs representative acting on their behalf — when creating the declaration in the HMRC system. The number must be unique within the declarant's account. The customs office does not generate the LRN; it accepts it as part of the declaration data and uses it as the basis for issuing the MRN.
Are the LRN and the MRN the same thing?
No — they are two different numbers. The LRN (Local Reference Number) is assigned by the declarant before the declaration is filed, as an internal identifier. The MRN (Movement Reference Number) is assigned by the HMRC system once the declaration is accepted, confirming that it has been registered. In practice, the LRN is essential for tracking the declaration before the MRN is obtained.
What are the consequences of an error in the LRN or a duplicated number?
Providing a duplicated LRN, or a number that does not comply with the required HMRC format, results in the declaration being rejected by the system. The declarant must then correct the number and refile the declaration, which delays clearance. For time-sensitive goods, such as food products, this delay can generate additional storage costs and contractual penalties.
How long should documentation containing the LRN be kept?
Documentation for customs declarations, including data containing the LRN and the associated MRN, should be kept for a minimum of 4 years under HMRC requirements — in practice, companies use a 5-year period for safety. The documentation should include a copy of the declaration, the MRN confirmation, invoices and transport documents, as the full set may be required during a customs control or tax audit.
Related guides
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