Mileage clocking

On older vehicles the cluster was a mechanical odometer that could be physically rolled back. On modern cars, the mileage is stored in multiple electronic modules — the cluster, the ECU, the body control module, and sometimes individual key fobs. Clocking a modern car requires changing all of them, and a single stale value is enough to expose the fraud.

The DVSA MOT history database is the single best free defence: the recorded mileage at each test is permanent. Any gap or reversal in the sequence is visible to anyone with the registration.