last year I'll followed a police car, with no blue lights or sirens going, along a dual carraige way at speeds getting close to 100mph. After a couple of miles they slowed to well below 70 so I slowed to 70 and passed them. I then got a set of flashing blue lights in my mirror and ,was of course, stopped. On asking me what speed I was doing I simply replied "I don't know officer I was simply matching your speed as I assumed thatyou not having your lights on would be keeping to the limit, and that is what i will say in court"
This resulted in one slightly peed off police man that realised he couldn't do me for speeding without hiim having to stand up in court and admit to speeding for no reason, a very very close inspection of my car, which he couldn't find any fault with (even checked there was water in washer bottle!) and all documents, which were all in order and then me being told to go on my way when he couldn't find anything at all to do me for.
I then went on my way, being very careful to stick to the speed limit as they followed me for a few more miles
the police do not have a right to break the speed limits, especially if they are not on a call, but when was the last time anyone saw a police car stopping a police car!