Not at all illegal, there is even one which runs from Keighley to Bradford. I'm not sure if there are any safety requirements that may prohibit carriage of bikes on the front of a vehicle (I wouldn't imagine so if tractors are allowed to drive along with a ruddy great digger on the front), but the use of buses to carry bicycles hasn't ever been, not I suspect will it be, illegal in the UK.
Bike buses?
Not at all illegal, there is even one which runs from Keighley to Bradford. I'm not sure if there are any safety requirements that may prohibit carriage of bikes on the front of a vehicle (I wouldn't imagine so if tractors are allowed to drive along with a ruddy great digger on the front), but the use of buses to carry bicycles hasn't ever been, not I suspect will it be, illegal in the UK.