Hi I had a really odd experience driving this evening and have been puzzling over it. I was driving along a duel carriageway when I noticed blue lights quite a way behind me and so I pulled into the inside lane and stayed there when I realised that not one but several police traffic cars were going along. I assumed there must have been a bad accident. After they had all passed, I pulled into the outside lane because I was behind three coaches which were all travelling quite slowly. After I overtook them, I went back into the inside lane and I was directly in front of yet another police car! I then had a horrible shock as the police car started flashing its blue lights, since if it had wanted to overtake it would have just moved into the outside lane I thought it wanted me to pull over and I panicked as I didn't know what I had done wrong. The worst thing was there wasn't anywhere I could pull over, as there was no hard shoulder for the forseeable distance but it just kept flashing its blue lights. So after a while (maybe a minute but it felt like to much longer!) I slowed right down, almost stopping, to see what it wanted - and it overtook me! I then had angry coaches flashing their lights but I don't know what I should have done. Does anybody know why the police car had its siren and lights on but wasn't overtaking? I was really shocked and shaky. Thanks.