From here:
265
The right-hand lane of a motorway with three or more lanes MUST NOT be used (except in prescribed circumstances) if you are driving
any vehicle drawing a trailer
a goods vehicle with a maximum laden weight exceeding 3.5 tonnes but not exceeding 7.5 tonnes, which is required to be fitted with a speed limiter
a goods vehicle with a maximum laden weight exceeding 7.5 tonnes
a passenger vehicle with a maximum laden weight exceeding 7.5 tonnes constructed or adapted to carry more than eight seated passengers in addition to the driver
a passenger vehicle with a maximum laden weight not exceeding 7.5 tonnes which is constructed or adapted to carry more than eight seated passengers in addition to the driver, which is required to be fitted with a speed limiter