UK law now permits Category B driving licence holders to drive an alternatively-fuelled vehicle weighing up to 4.25 tonnes. The vehicle must not be driven outside of Great Britain. It must be used for the transportation of goods, not be towing a trailer and the driver must have completed a minimum of 5 hours training.
Training may only be provided by members of the DVSA-endorsed NRI, or by members of the NVDIR which is recognised by DVSA.
An alternatively-fuelled vehicle is a vehicle powered by electricity, natural gas, biogas or hydrogen, or hydrogen and electricity.
A certificate is issued on completion of training.
Note that anyone found driving an alternatively fuelled vehicle between 3.5 tonnes and 4.25 tonnes on a Category B licence without having done the 5 hours training would be guilty of an offence under the Road Traffic Act (1988).