I do have a question as well actually. 8 months ago, it was dark and I was driving along a 40mph road, going 40 having being out at a pub (not drinking alcohol) and was now on my way home. A car came up quite close behind me and the lights were quite bring in my rearview mirror and kept changing colour (to orange and back to yellow), which was quite distracting. I flipped the mirror down and kept on going.
I then came up behind a car that was going 30, meaning I had to slow down, flipping the mirror up so I could see behind me better I noticed the annoying car was still on my tail, so indicated and overtook the car infront, though I did go 45 to get past it quickly. Nothing was coming the other way, and I thought "yes, got away from that annoying car," unfortunately not. It overtook as well and then drove up right behind me again. The road then changed from 40 to 60 and I was off, up to 60mph, with this annoying car still right behind me.
Soon, however I caught up with some other car going 40. Now I understand that in a country lane, it is not necessarily sensible to speed along at 60, but this was a main road, pretty wide. I would have overtaken that car straight away, but couldn't due to the various bends that stop you seeing far in the other way, so I waited, biding my time, with this annoying car right behind me, with the strange colour changing headlights.
Finally I got past a dangerous bend with straight road, nothing coming so I overtook the 40mph car, so did the annoying headlit car, then more lights appeared on it, blue ones on the top, however just coming up to a roundabout I couldn't stop safely, so I though "*** it, I'll stop when it's safe to do so." The police car stop flashing aswell, I'm sure he understood why I didn't stop at that moment, and continuing to follow me, at the next safe bit of road, the lights flashed again and this time I indicated and pulled over.
Apparently I'd done two things that were wrong. I counted one, going 45 when I overtook the first car in the 40 zone. But apparently the other place was unsafe too. I started to argue, but cut myself short and just politely agreed and apologised. They checked out my car, asked my name and then said "on your way." I drove home. Now this annoyed me slightly, especially due to the fact that this police car had been driving up close for the whole journey

The next thing annoyed me even more a few months later...
I was driving along the same patch of road, having come accross several police cars, that had gone in different directions. A random merc came up behind me, right on my tail (they like doing it when you are going at the speed limit = 40 and then later on the road = 60) and then some other car was right behind him, I was begging for it to be a police car, he was on my tail all the way up to the roundabout, then undertook me at 50-60 mph (roundabout aint that big) I was thinking "please be a police car, car behind and follow him," The merc went onto the dual carriage way, the other car came up closer to me, didn't stop the merc and as I turned off at my roundabout he drove back the way he had come.
Why did the policeman not stop the merc for what he did and yet be perfectly happy to stop me a few months earlier when I even gave that 40mph car plenty of space until I overtook him?
P.S. Sorry for the wall of text.
