How to pass the MOT ...buy a silver car and get it tested on Friday

IS YOUR car due its MOT soon? Think twice before visiting the test centre on a Monday, especially if you drive a white car, warn experts.

They examined test data from 121million cars and discovered the chances of failing the test are higher on Monday than on Friday and Saturday.

The academics also found that silver cars are more likely to pass the MOT than any other colour, while white vehicles are the most likely to fail.

Their research revealed that Central London is the best place in Britain to have the test, as it has the lowest failure rate, while cities and towns in Scotland, such as Dundee, Kirkcaldy and Aberdeen, see the most cars fail.

Economics professors Oleksandr Talavera and Shaun Hargreaves Heap are due to present their findings this week at the Royal Economic Society’s annual conference at Warwick University.

They studied MOT data on British vehicles between 2005 and 2013 stored on a Ministry of Justice website and came up with a raft of surprising findings.

Prof Talavera said he suspects that mechanics tend to pass MOT tests more easily on Friday because of a so-called ‘weekend effect’, which encourages workers to give a more positive result, as they may feel pressure that the customer needs to use the car over the weekend, or because they want to finish work early. He said: ‘The failure rate on Monday is usually at 36 per cent nationally.

‘But on Friday, it is more than two per cent less. On Saturday, it’s five per cent less than Monday. So if the ‘weekend effect’ can do that, it probably means that if you take your car just before the Christmas or Easter holiday, you are more likely to pass the test.’

The researchers believe that the reason why a silver car passes its test better than cars of other colour may be because it has become associated with reliability.

In their paper, the academics explain: ‘A grey or silver car is associated with balance, high quality and reliability and this would be consistent with our evidence that such cars are more likely to receive benefit of the doubt in tests.

‘It is also the logo colour for Mercedes-Benz and Honda, two brands that enjoy a reputation for reliability.’

Prof Talavera found that a Mercedes vehicle is the most likely to pass its MOT test, compared with any other car with the same mileage and age.

Mercedes cars typically have a 15 per cent failure rate, followed by Porsches at 18 per cent, and Lexus at 21 per cent.

Conversely, Renaults have the highest fail rate at 45 per cent, followed by Rover at 42 per cent and Alfa Romeo at 41 per cent.

Failure rates in Central London were lowest at 20 per cent, followed by the Essex towns of Romford at 26 per cent and Southend-onSea at 28 per cent.

‘Where you tend to get fewer garages and more cars, the pass rate is higher,’ said Prof Talavera.

Annual MOT tests were first introduced in Britain in 1960 for vehicles that were more than ten years old.

Now, any vehicle over three years old must pass the yearly test.

‘Weekend effect’ leads to higher pass rate