A good few years ago, I was on the M6, in lane 3 overtaking a line of vehicles in lane 2, when a dark coloured Range Rover approached me behind, and as it got nearer, blue lights illuminated, so I naturally 'squeezed' in between the vehicles I was passing to allow the Range Rover to pass, thinking it was an unmarked Police or emergency services vehicle, which it did at speed. I did notice it was a top spec model, not the more basic version commonly used by the Police. It was also on a private reg, which was a bit suss and the main reason I decided to report it. The Police operator confirmed that it wasn't a Police Vehicle. Several miles down the M6, it had been stopped, and later feedback from the Officer dealing was that it was a 'Joe Public' driver who had fitted the blue lights himself - I can only presume to possibly assist him through conjested areas of traffic...he ended up in Court, but unfortunately, I don't know the result. What a plonker....but the other implications of any possible intended actions could be quite serious.