From the DVLA website:
Why you need an MOT certificate
It is generally an offence to use on a public road, a vehicle of testable age that doesn’t have a current test certificate, except when:
taking it to a test station for an MOT test booked in advance
bringing it away from a test station after it has failed the MOT test, to a place of repair
taking it to a place, by previous arrangement, where problems that caused the vehicle to fail its MOT test, can be repaired
bringing it away from a place where the problems with the vehicle have been repaired
Even in the above circumstances you may still be prosecuted for driving an unroadworthy vehicle if it doesn’t comply with various regulations affecting its construction and use. Your car insurance may also be invalid.
http://www.direct.gov...ehicle/Mot/DG_4022108