What is UN Number?
A UN number is a four-digit identifier assigned to a dangerous substance or article for transport purposes.
Great Britain applies ADR through the Carriage of Dangerous Goods Regulations. Classification, packaging, marking, documents, vehicle equipment and training must match the actual substance, quantity and mode of carriage.
| Aspect | What to know |
|---|---|
| Core meaning | Four-digit identifier |
| Operational use | Preceded by UN |
| Control point | Basis for ADR lookup |
| Key caution | Must match proper shipping name |
How does it work in practice?
It is used with the proper shipping name, class and packing group to determine the applicable ADR entry and controls.
Before loading, the consignor and carrier verify the UN number, proper shipping name, class, packing group, quantities, exemptions and transport document. Vehicle and crew requirements are then checked against the real load.
Decisions, exceptions and reference numbers should be recorded in the transport order or relevant system. This creates a clear audit trail of the information available and the actions taken by each party.
Key points to check
- Four-digit identifier
- Preceded by UN
- Basis for ADR lookup
- Must match proper shipping name
Always check current contract terms and official guidance as the correct application may vary by vehicle, goods, route, port, customer role or selected customs procedure.
Why does it matter for urgent transport?
Dangerous goods must never be treated as ordinary freight merely because delivery is urgent. Complete classification and compatible equipment are required before a vehicle is assigned.
Good preparation prevents a fast vehicle movement from being delayed by missing documents, unsuitable equipment, incorrect classification or denied access at the collection, border or delivery point.
Frequently asked questions
What is UN Number used for?
A UN number is a four-digit identifier assigned to a dangerous substance or article for transport purposes. It is used with the proper shipping name, class and packing group to determine the applicable ADR entry and controls.
Is UN Number mandatory?
Application depends on the substance, quantity, packaging and available exemptions. ADR 2025 and current HSE guidance are authoritative.
What should be checked before transport?
Confirm the parties, goods, documents, reference validity and requirements along the actual route. Where the rule is regulatory, use the latest guidance from the competent UK authority.
Sources: HSE – Carriage of dangerous goods and GOV.UK – Moving dangerous goods. Editorial review: 13 August 2026.