Heading back from Chiswick to Berks, I was racing with a Mini, who was first blocking me at 90mph, then started flash me with its beam. M4 between J8/9 and 10 is always pitch dark, but there was no need for any beam. I so wished for a police to show up from the hard shoulder and stop this psychotic Mini, and that's pretty much what happened.
Police might have gotten me, I was doing 100mph to get away from the Mini after all, but Police went for Mini with stupid beam on doing 82mph, perhaps because I was behind the police car and didn't make any sudden movement.
Anyone knows this; go with the flow, just only when you are on the road. And NEVER take over a police car.
