MOT
Major defect
MOT defect category for a fault that may affect the vehicle's safety or have an environmental impact. The vehicle fails the test.
A Major defect is a fail but is not, on its own, classed as an immediate danger. If the previous MOT is still valid and the failure is not Dangerous, the law permits driving the vehicle for repair, although most owners arrange recovery.
Examples include a brake disc that is significantly worn or contaminated, a headlamp aim that is out of tolerance, or a parking brake that does not meet the minimum efficiency.