Controversial planned changes to the MoT test will increase the number of unsafe vehicles on Britain's roads, according to Government figures obtained by leading consumer motoring site HonestJohn.co.uk.

The Government's plans to extend the annual roadworthiness test from three to four years – which is currently undergoing a consultation period - could mean 385,000 vehicles that would have failed their first MoT will slip through the net and remain on the road unrepaired.

The leading consumer motoring site analysed millions of previously unseen MoT records from the Driver and Vehicle Standards Agency (DVSA) and found that one in six cars were refused a roadworthiness certificate during the first MoT, with most failing due to unsafe brakes, lights and tyres.

The revelation comes as HonestJohn.co.uk published the MoT Files for the first time in three years, following a Freedom of Information (FoI) request and protracted fight with the DVSA to make the data public. Success in this long-running battle means that for the first time in years owners and prospective buyers once again have detailed access to the latest MoT records and reasons for failure. It has been published in full at HonestJohn.co.uk/mot

The publication of HonestJohn.co.uk’s MoT Files means that consumers can easily spot common failures by make, model, year of registration and postcode based on real world data. HonestJohn.co.uk’s MoT Files provides simple and detailed access to more than 400m Government data records and represents another significant step forward for consumers who want to make better informed decisions about their next car purchase.

Broken down by model, the detailed data reveals that the worst performing car for the first MoT was the Peugeot 5008, with only 67% of cars registered in 2013 passing in 2016. The Citroen DS4 was second (73%) while the Renault Megane and Ford Galaxy were third and fourth, with a respective 74% and 75% pass rates. The Chevrolet Spark completes the list with a pass rate of 76%

The worst car manufacturers for the first MoT in 2016 were Chevrolet, Citroen and Dacia, with respective pass rates of 78%, 79% and 81%. Honda, Porsche and Subaru all hold a collective first place, with the trio showing a first year average pass rate of 91%. 

The car with the highest pass rate during the first MoT in 2016 was the Lexus RX 450h with an impressive score of 94%. The Honda Jazz was second (93%), followed by the Mazda MX-5 (93%), Volkswagen Golf Plus (92%) and the Audi Q5 (92%).

Daniel Powell, Managing Editor of HonestJohn.co.uk said: “Many of the common failure items are down to general maintenance, rather than a particular fault with the car.

“The Government’s proposal to extend the first MoT from three to four years will effectively give irresponsible motorists a free pass to drive dangerous cars for an additional 12 months, without any mandatory safety checks.”

Top five causes of failure during a car’s first MoT at three years
1) Lighting -169,000 failures
2) Tyres – 101,000 failures
3) Driver’s view of the road – 98,000 failures
4) Brakes – 60,000 failures
5) Suspension – 27,000 failures

Top five cars for passing the first MoT
1) Lexus RX 450h – 94%
2) Honda Jazz - 93%
3) Mazda MX-5 – 93%
4) Volkswagen Golf Plus - 92%
5) Audi Q5 - 92%

Bottom five cars for passing the first MoT
1) Peugeot 5008 67% pass rate
2) Citroen DS4 73% pass rate
3) Renault Megane 74% pass rate
4) Ford Galaxy 75% pass rate
5) Chevrolet Spark 76% pass rate