This is why I hate driving in Britain..not all of it of course, but a lot of places in which you get people just like this loon. Seems that seldom can you go anywhere without some pricks tail-gating, speeding, dangerously over-taking, using their car as a weapon, being verbally and physically abusive to other road users including cyclists minding their own business. This includes works representatives who seem to think they are above the law and everyone else..
I can tell you this, the people who do this wouldn't last long in the States. The cops and the courts wold be onto them a lot quicker than they are here especially if you have video footage. Completely unacceptable attitudes.
This is why it's always advisable to supply dash-cam footage of the ENTIRE interaction. Because otherwise it's one person's word against another.