The MoT test is due a major shake up this year. There will be tougher rules for diesel cars, as well as three new defect categories - Dangerous, Major and Minor.

Under the new rules, which come into force on May, 20 2018 , cars will automatically fail the test if they get a Dangerous or Major fault.

Here is everything you need to know about the changes.

Dangerous, Major and Minor defect categories

Dangerous, Major and Minor defect categories will be introduced to the test in May - the latter will result in an automatic failure.

If your car has a minor issue this will be recorded on its MoT certificate and also online, just as it is now.

An example of how the new defect categories will be applied is as follow - if a steering box is leaking oil this would be classed as a minor fault, however if the oil is leaking to the point that it is dripping, then this would constitute as major defect and the car would fail the test.

The new categories will be applied to all cars, and are being introduced to meet a new EU directive.

Diesel cars

Any car fitted with a diesel particulate filter (DPF) that emits “visible smoke of any colour” will get a Major fault, and automatically fail its MoT, according to specialist motor site autoexpress.co.uk

Testers will also be urged to check to see if the DPFs have been removed or tampered with, and can refuse to test any car if “the DPF canister has clearly been cut open and re-welded”, unless the owner is able to prove to it was done for a legitimate reason, such as filter cleaning.

Other changes

Other changes include checking reverse lights and inspecting brake discs to see if they are “significantly or obviously worn”.