In Great Britain MOT testing centres are regulated and licensed by the Department and Transport and DVSA for the purpose, and the individual testers carrying out the inspections also have to be trained and certified. The decision to pass or fail each presented vehicle comes down to the discretion of the tester following the guidelines issued by the DVSA.
The MOT test covers the following aspects:
An MOT test certificate confirms that at the time of test, the vehicle has met the minimum acceptable environmental and road safety standards. It does not mean that the vehicle is roadworthy for the life of the certificate. The test does not cover the condition of the engine, clutch or gearbox. Maintenance that is necessary for the reliable and efficient operation of the vehicle but not its safety forms part of a service inspection that is recommended by manufacturers, but is not a legal requirement for operating the vehicle on the public highway.
For more information visit https://www.gov.uk/government/organisations/driver-and-vehicle-standards-agency