What it means
The vehicle’s individual identity number, distinct from the registration number displayed on its plates.
The VIN is usually stamped into the chassis. Use it to compare the physical vehicle with its foreign registration record, customs documents and technical evidence. Copy it carefully: an unclear character is a reason to check the original, not to choose whichever version appears most often.
If the number is missing, altered or inconsistent, raise the issue before submission. DVLA has assessment procedures where a vehicle’s identity is in question. Keep photographs and supporting records securely, and do not try to resolve a discrepancy by changing or restamping the number yourself.