This is a term for a vehicle that has been declared a total loss by an insurer following accident damage or theft.
Although write-offs can legitimately be allowed back on the road, almost half are beyond repair. Look for the ones that have passed an independent inspection, such as the Condition Inspected register. Since 1997, the Association of British Insurers (ABI) has provided classification of damage to vehicles that have been written off. Category 'A' or 'B' must never reappear on the road, whilst 'C' and 'D' may do so following proper repair, passing an independent Thatcham-approved structural examination.