Is it illegal to sell a car that is not roadworthy?

What counts as unroadworthy

A motor vehicle or trailer is in an unroadworthy condition if using it on a road in that condition would be unlawful under the construction and use regulations about brakes, steering gear or tyres, or about the construction, weight or equipment of vehicles, or if using it on a road would involve a danger of injury to any person. The Great Britain test is in section 75(3) of the Road Traffic Act 1988 and the Northern Ireland test is in article 83(3) of the Road Traffic (Northern Ireland) Order 1995.

GOV.UK says you are responsible for making sure your vehicle is safe to drive, and that it can be unsafe even if it has a current MOT certificate, so an MOT does not settle the question.

Who it applies to

The offence is not limited to dealers. No person may supply a vehicle in an unroadworthy condition, and supplying includes selling, offering to sell or supply and exposing for sale. It is also an offence to alter a vehicle so that using it on a road would be unlawful under the rules on its construction, weight or equipment, or would involve a danger of injury, and to cause or permit either.

The defences

A person is not convicted if they prove the vehicle was supplied for export, or that they had reasonable cause to believe it would not be used on a road in the country concerned (Great Britain under the Act, Northern Ireland under the Order), or would not be used on a road until it had been put into a lawful condition.

The “reasonable cause to believe” defence is narrower for a seller acting in the course of a trade or business: if they expose a vehicle for sale they must also prove they took all reasonable steps to ensure any prospective purchaser would know that using it in its current condition on a road would be unlawful, and the same applies to an offer to sell.

It does not cancel the sale

Both provisions say they do not affect the validity of a contract or any rights arising under it, so the offence sits alongside your contractual rights rather than replacing them. Our answers on buying privately and on a dealer who refuses to repair cover those rights.

Reporting a seller

GOV.UK names Citizens Advice in England and Wales, Advice Direct Scotland in Scotland and Consumerline in Northern Ireland, and says they can refer a complaint to local Trading Standards.