you could see coppers driving too so it was very clever but thats bad if you ask me u just could not tell at all
If you're not doing anything wrong, you've nothing to worry about have you? Unmarked cars are nothing new, they're just getting better at hiding everything. Black VRS's with a forest of aerials on the roof are a thing of the past now. Surrey have totally standard looking Focus ST's now (and marked-up ones as well which do look very impressive).
One of my colleagues (I stress
colleague, not acquaintance) has a Civic Type R (new one - horrible car btw) and had one of these STs move in behind him. So he floored it thinking this guy was trying to begin a willy-waving contest. Three points later, he learnt that ego has no place on the road and to look more carefully at who is in the driving seat in future. And that torque rules.