Greeny,
When confronted with that type of situation there is an easy solution to this which is actualy encouraged when you get pillocks on the road who try and run you of it.
Take down their licence number, next and most importantly, take down the licence number of someone nearby which has witnessed the incedent. If you have someone in the car with a camera phone take a couple of happy snaps off your new mate.
Then get on the phone to Mr Plodd and report the incident.
They will chase the tosser up and with the new laws will charge him with reckless driving or impound their cars under the hoon laws.
Quite often if you can give the details about where the pill is they will actually try to catch them on the road.
Whatever you do though, don't stop and get into a barney with them, there are more and more dickheads out there looking for an excuse to go feral on some poor driver, my dear old dad (a pensioner) has had 2 seperate incidents meeting this charming group of peoples so far


( I've never laughed so much as when he told me about them

)