... I did exactly that, tonight.
Travelling northbound to meet Foxycav. I was in lane 3 of the M5, progressively overtaking everything in lane 2. I couldn't go any quicker - limited by car in front, etc.
Mk4 Astra, comes up behind me. Heavily modified, funny coloured blue lights. Sitting so close to my rear I feel genuinely uncomfortable.
Continually flashes main beam, seems to drop back, and then charge at me like a tonne of bricks... and so on.. clearly wants me out the way, despite I am already doing an, erm, steady 70... and have nowhere to immediately pull in until I finish overtaking a row of slower moving cars / vans.
I move over as soon as I can, muttering a few unsavoury words under my breath.
He overtakes me, driver holding some sort of mobile device in one hand, pasenger giving me "V's", and then proceeds to do the same to another car in front.. despite said car also overtaking stuff, and not really having anywhere to go
The chap then seemed to decide he wanted to do 40mph in lane 3 of a quick moving motoway... no need to describe how disruptive that is... cars had the choice to either undertake... or bunch up behind him...
He was a danger, on such a busy M way... I called it in, hopefully he got picked up!