Travelling back north around the J15 area I noted a car about a mile behind traveeling at a considerable rate of eek, headlights flashing. Suspicious I eased off into lane 2, an awaited. Sure enough, about 200 yards behind me (and other traffic) blue lights appeared in the front grill. Car continued to barge it's way through the traffic. What surprised me most, was the fact it was a Toyota Avensis, either very dark green or black (too dirty to tell) and was a T plate. I'd have thought that was getting a bit old for unmarked motoway plod, but well, apparently not.