Driving on the A316 today heading towards London, the road at this stage is two lanes heading towards the first roundabout you get to and I am in the outside lane overtaking some cars and the next second this guy on a motorbike is right up my ****. I am already going faster than the limit and cannot pull in as there are cars on my left so I stay in the outside lane go round the roundabout and continue on. By this time the guy has lifted his visor and whilst still almost touching my rear bumber starts waving his hand around telling me to get out the way, I show him the finger which I know is silly and I should have just ignored him but you know what its like when someone is tailgating, it gets your back up. Anyway he goes crazy, he pulls alongside me and starts yelling his head off and punching his helmet, then he starts riding his bike as if he is going to ram my car but always stopped before he actually hit the car, all this whilst travelling at 40-50 mph. I eventually wind my window down and he's shouting "pull over you #@#@ I am going to kill you", not being the biggest/hardest bloke around I say no and wind back my window, he then carries on shouting at me, punches his own head a few more times and then accelerates of into the distance.