MRN, DUCR and LRN – What They Mean and When Each Number Matters

MRN, DUCR and LRN come up in the same conversation very often, but they don't mean the same thing. In practice, many problems with clearance or movement to the port aren't down to a "missing number" at all, but to confusing which number belongs to which stage of the process.

This guide explains the simplest way to tell them apart and shows when these references come up during import, export and UK-EU transit. If you need support with the full process, also see our UK-PL customs consultancy for import and export.

MRN - Movement Reference Number

The MRN is a reference number generated once a declaration is accepted, or as part of certain procedures such as transit. In practice, the MRN is one of the main numbers you use for the onward movement of goods, submitting documents, and checking status.

GOV.UK notes, for example, that for declarations in the Customs Declaration Service you can use the MRN when sending supporting documents or when amending a declaration. In transit, the MRN is also the key number for movements in NCTS.

DUCR - Declaration Unique Consignment Reference

The DUCR is used as a unique consignment reference in certain declaration scenarios, particularly for simplifications and in export. GOV.UK describes it as a mandatory reference under certain SDP models and notes that it should be consistent between linked declaration stages.

In the context of GVMS, the DUCR can also be the reference that needs to be provided for export declarations lodged with CDS.

LRN - Local Reference Number

The LRN is a local reference number created by the declarant. It's used to track a declaration and distinguish records at the stage before the definitive system references are generated. GOV.UK also notes that duplicate LRNs can lead to a declaration being rejected within a certain time window.

Where most mix-ups happen

• when a company confuses a transit MRN with an import declaration MRN,
• when the wrong reference is entered for a GVMS movement,
• when the operations team doesn't know whether it's working with a local number or one already confirmed by the system,
• when different parties in the process use their own shorthand without a shared vocabulary.

A practical way to approach these numbers

1. Always establish which stage of the process a given number relates to.
2. Separate local numbers from references generated by the customs or transit system.
3. For GVMS movements, check exactly which type of reference needs to be entered.
4. Don't assume that because a number "looks right" it's suitable for every stage of the movement.

Summary

MRN, DUCR and LRN play different roles. The sooner a company builds a simple, internal order around these references, the less chaos there will be during clearance, corrections and communication with the carrier. If you'd like us to sort this out in the context of your own import or export model, get in touch with us.

Official sources

• GOV.UK: Create a goods movement reference
• GOV.UK: Upload documents and get messages for CDS
• GOV.UK: Amend or cancel a CDS import declaration
• GOV.UK: Simplified Customs Declaration Process - supplementary declarations
• GOV.UK Trade Tariff: Group 2 references

How to make this process more effective in practice

The best results come from a consistent way of working: one master data list, one responsible person and a fast check of documents before goods start moving. This helps a company cut down on corrections, transport delays and unnecessary operating costs.

Frequently asked operational questions

What should you do if the data on your documents differs?

Hold the declaration and align the source documents first. It's best to resolve discrepancies before clearance, not after the process has already been stopped.

Who should be responsible for the final data check?

One person on the company's or operator's side who has full visibility of the commercial, transport and customs documents.

When is it worth carrying out an internal process review?

After every problematic clearance, and whenever there's a change in product, delivery route or sales model.

Related articles

• EORI number in 2026
• IPAFFS in 2026
• The T1 document in 2026

If you'd like to work through this topic using your company's own data, send us a cooperation form and describe the planned movement of goods.