MRN Number UK: Format, Meaning & How to Check (2026 Guide)
If you move goods between the UK and the EU, sooner or later you will need an MRN number. The Movement Reference Number is one of the most important codes in the UK customs system — without it, a declaration is not registered and a truck can be turned away at the border. This 2026 guide explains what an MRN number is, its exact 18-character format, when it is issued, how it differs from a GMR, and how to check one — including what the free GOV.UK checks can and cannot tell you. Start with the format checker below.
MRN Format Checker
Paste a Movement Reference Number to check it against the structure HMRC documents for CDS. This checks the format only — it runs in your browser, nothing is sent anywhere, and it cannot show whether a declaration has been cleared. For status, see how to check an MRN below.
What is an MRN Number?
An MRN (Movement Reference Number) is, in HMRC's own words, "a globally unique identifier for a declaration assigned by CDS once a declaration is submitted." In plain terms: the moment your customs agent files a declaration in the Customs Declaration Service (CDS), HMRC issues one MRN that confirms the declaration is registered and being processed. CDS generates an MRN automatically for every import and export declaration, including pre-lodged declarations submitted before the goods arrive.
MRN Number Format Explained
An MRN is exactly 18 characters long, made up of letters and numbers. According to HMRC's CDS Movement Reference Number guide, it breaks down as follows:
- Year — the current year as two digits (for example, 2026 becomes
26) - Country code — the two-character code for where the declaration was made; for the United Kingdom this is
GB - Reference — a 14-character alphanumeric string randomly generated by CDS
So a UK MRN issued in 2026 follows the pattern 26GB + 14 characters. If a number you have been given is not 18 characters, or does not start with a year and a country code, it is not a valid CDS MRN — double-check it before presenting it at the border.
When Do You Get an MRN Number?
An MRN is generated at the moment a declaration is submitted. In a typical UK–Poland movement you may see more than one:
- Export MRN — issued when your agent submits the export declaration in HMRC CDS before the goods leave the UK.
- Import MRN — issued when the import declaration is filed in the destination country's system (for example Poland's PUESC).
- Transit MRN — issued when a T1 transit procedure is opened in the New Computerised Transit System (NCTS). If your goods travel under transit, a broker such as this UK–EU transit and T1 clearance service opens the NCTS movement and returns the transit MRN to your driver.
MRN vs GMR — What's the Difference?
These two references are frequently confused, but they do different jobs:
- MRN — identifies the customs declaration (what goods you are moving and under which procedure).
- GMR (Goods Movement Reference) — identifies the vehicle crossing in the Goods Vehicle Movement Service (GVMS). For an import, the MRN is added into the GMR. The driver needs the GMR to check in at GVMS ports such as Dover, Folkestone or Holyhead.
HMRC is clear that goods cannot move on GVMS routes without a valid GMR, and a vehicle will be turned away at check-in if the GMR is missing or the vehicle, trailer or container details do not match. Both the MRN and the GMR are normally prepared by your customs agent before the truck departs and sent to the driver in minutes. For a deeper look at the declaration behind the MRN, see our guide to UK export declarations in CDS.
How to Check an MRN Number (UK MRN Checker)
Search for a "UK MRN checker" and you will find no official page where anyone can type a Movement Reference Number and see the declaration behind it. That is deliberate: declaration data belongs to the trader and their appointed agent. What exists instead is a set of separate checks, and the right one depends on what you are actually trying to find out.
1. "Is this even a valid MRN?"
This is a structure question, and you can answer it yourself with the format checker above: 18 characters, two digits for the year, a two-letter country code, then a 14-character reference. A number that fails this test will never work at the border, whoever sent it to you.
2. "Has my declaration been cleared?"
Declaration status lives in HMRC's Customs Declaration Service, or in the commercial customs software used to file it. Only the trader and the agent acting for them can see it. A status of "Released" means the goods have cleared customs and can be collected from the customs-controlled area. For import declarations filed abroad — in Poland, for example — the status sits in that country's system (PUESC / e-Klient), not in CDS.
3. "Is my truck about to be stopped?" — the one public GOV.UK check
There is a free GOV.UK service that anyone holding the reference can use: "check if you need to report for an inspection". HMRC's GVMS guidance states that both the driver and the haulier can use it to see "the most up to date status of the GMR". Note the important detail — it takes the GMR, not the MRN. This is the single most common reason people searching for an "MRN checker" come away empty-handed: the movement is tracked under the goods movement reference, while the MRN sits inside it.
The status is not static. HMRC describes carriers changing "the state of all GMRs on the vessel to 'embarked'" during the embarkation process, and says the service will "update the GMR to show the most current status of the goods and will advise if there are any holds in place".
4. "Is my transit movement still open?"
For transit, HMRC set out the rule in a February 2026 newsletter to traders: when a movement is discharged you receive an IE045 message if fewer than 60 days have passed since release to transit, or a letter if more than 60 days have elapsed. HMRC is explicit about what silence means: "If you have not received a notification of discharge either digitally or via letter, the movement can be assumed to be open and the MRN still in use."
Two practical consequences follow. First, an open movement keeps your guarantee committed — HMRC tells traders they "should be monitoring all instances of guarantee use and the associated transit MRNs" raised against their Guarantee Reference Number. Second, do not expect HMRC to run the report for you: the same newsletter states that HMRC "will not provide information where a request is made for information in bulk about MRNs currently in use". To close an individual movement you supply proof the procedure ended — for example a document certified by the customs authorities in the country of destination, or a certified import declaration.
Presenting the MRN at the Border: Barcode, App or Paper TAD?
Having a valid MRN is not the same as being able to produce it. Under NCTS Phase 5, HMRC's rule is that the MRN "must always be accessible by the driver or person in charge of the goods to ensure that it can be provided where required" — so a number sitting in an office inbox is a problem waiting to happen at an office of transit.
- At non-GVMS border locations, drivers must "present the MRN as a linear barcode for Border Force to complete office of transit and destination formalities". A plain text message with the digits is not enough where a barcode scan is expected.
- Paper Transit Accompanying Document (TAD) — HMRC required the paper TAD to be carried "with all goods up to and including 22 January 2025". After that date, "where electronic presentation is not possible, a paper TAD will always be accepted". In other words, paper is now the fallback rather than the default, and it never stops being valid.
- From authorised consignor premises, the MRN and barcode can be sent to the driver electronically — by app, email or SMS — or handed over as a paper TAD, depending on what the national administrations on the route accept.
What to Do if an MRN Is Not Working
If an MRN appears invalid or a movement is stuck, check the basics first: confirm the number is 18 characters, that it has not been mistyped, and that it matches the correct leg of the journey (export, import or transit). If the declaration was pre-lodged, remember it only becomes "arrived" once the goods physically reach the frontier. When in doubt, ask the agent who filed the declaration — they can see the live status in CDS and reissue documents if needed.
MRN Number Checklist
- ☐ Confirm the MRN is exactly 18 characters (year +
GB+ 14 characters for UK). - ☐ Match each MRN to its leg: export, import or transit.
- ☐ For GVMS routes, make sure the MRN is added into a valid GMR before the driver checks in.
- ☐ Verify vehicle, trailer and container details match the GMR.
- ☐ Track the declaration status and wait for "Released" before collection.
- ☐ Make sure the driver can actually produce the MRN — as a linear barcode at non-GVMS locations.
- ☐ For transit, watch for the IE045 discharge message; no notification means the movement is still open and the guarantee is still committed.
- ☐ Use "check if you need to report for an inspection" with the GMR to see holds and inspection calls.
- ☐ Keep every MRN on file — HMRC may ask for it during post-clearance checks.
Mini-FAQ: MRN Numbers
How long is an MRN number? An MRN is 18 characters long — two digits for the year, a two-character country code (GB for the UK) and a 14-character alphanumeric reference generated by CDS.
Is an MRN the same as a GMR? No. The MRN identifies the customs declaration; the GMR identifies the vehicle crossing in GVMS. For imports, the MRN is included inside the GMR.
Who issues the MRN? HMRC's Customs Declaration Service (CDS) issues it automatically the moment a declaration is submitted.
Can I look up someone else's MRN? No. Declaration data is only available to the trader and their appointed customs agent; there is no open public MRN lookup.
Do I get a new MRN for every shipment? Yes. CDS issues a unique MRN for every declaration, so a single UK–Poland trip can involve separate export, transit and import MRNs.
Is there a public UK MRN checker? Not for declaration status — that data is restricted to the trader and their agent. The free GOV.UK service "check if you need to report for an inspection" shows the current status of a movement and any holds, but it takes the GMR, not the MRN. You can check an MRN's 18-character structure yourself with the format checker on this page.
How do I know a transit MRN has been discharged? HMRC sends an IE045 message if fewer than 60 days have passed since release to transit, or a letter if more than 60 days have elapsed. If no notification arrives, HMRC says the movement can be assumed to be open and the MRN still in use.
Sources (gov.uk)
- HMRC — CDS Movement Reference Number (MRN) guide
- GOV.UK — Create a goods movement reference (GVMS / GMR)
- HMRC — GVMS processes at the border and during crossing
- HMRC — February 2026: Monitoring in-use Movement Reference Numbers (MRNs)
- HMRC — NCTS Phase 5: Electronic Movement Reference Number (MRN)
Customs procedures change. Always confirm current requirements on gov.uk before acting on them.
