An undercover investigation into UK car garages suggests the vast majority miss simple mechanical faults, consumer watchdog Which? has said.

Which? took cars with four deliberate faults to 62 firms including both franchises and independent sites.

Some 87% missed at least one problem, such as a deflated spare tyre or low brake fluid. All the faults were serious enough to cause a crash.

A number of codes of practice have been introduced to improve standards.

However, Which? called the latest investigation a "worrying snapshot of an industry that desperately needs to clean up its act".

Only eight garages fixed all of the problems on the vehicles, which were between three and six years old, while five did not rectify a single fault.