CAP has warned consumers not to take recently released MoT failure rate data at face value.

According to CAP a raw list of MoT failure rates risks misleading consumers by unfairly branding some car makes and models as unreliable or even potentially unsafe.

MoT failure rates are influenced by a wide range of factors over which the manufacturer may have no control. And the raw failure rate data fails to reveal the reasons for failure, which may be as minor as a worn-out wiper blade or dead light bulb – both problems which can be rectified in moments and for just a few pence, says CAP.

CAP’s Mark Norman said: “The problem with this story is that it implies the higher the failure rate the worse the car. We all know that an MOT is nothing to do with reliability.

"For instance, the most common overall reason for failure is lighting and signalling. But nobody could blame a manufacturer for a blown bulb or misaligned headlight.”

Another factor is the profile of the car’s owner and whether they adhere to the manufacturer’s service and maintenance schedule.

Some car owners – for example older drivers or those who have paid for their own car – will take more care of their vehicle and ensure minor faults are rectified before reaching the MOT testing station.

The type of use a car typically undergoes will also have a significant impact. For example, broken suspension springs are now a very common reason for MOT failure, with potholes and traffic calming humps cited as the cause. If a car is largely driven on short journeys in urban areas where potholes or humps are most common, it is more likely to fall foul of that problem than a car which generally spends most time on well-maintained motorways.

Mark Norman said: “Many company car drivers are routinely asked to take their car to the MOT station just before the end of a three year contract to ensure the vehicle can be easily sold on into the used market as soon as they hand it in.

“Those cars are highly likely to have minor faults which the driver has not rectified and will therefore almost routinely fail the test. But that does not mean there is anything fundamentally wrong with them.

“This means the typical company car is likely to show up in a negative light within figures such as those released to the BBC.

“It is unfortunate that VOSA released only the minimum of data required to comply with the Freedom of Information request.

"This means the data as it stands is of passing interest but of no real value to consumers and runs the risk of unfairly tarring some models with the reputation of unreliability.”