you'd have a hard job proving he knew he had a bus behind him: the wonderful thing about London's bus lanes is that they're usually empty outside rush hours. But there ought to be a charge of reckless endangerment or something similar that could be used.
He will probably end up doing 1/2 hour community service, or a joggers correction course , knowing the soft touch of the UK law, and that is even if the case makes it to court at all?.
// He will probably end up doing 1/2 hour community service, .....blah blah yawn [all this comment is crap you know] ......... if the case makes it to court at all?.//
no no - he will probably get a customer care medal from the firebrand leftist islamic Mayor of London !