Not sure what department ie police dvla or council.but there are vans with cameras fitted to each corner of the roof that drive around 24/7.checking car number plates ie tax insurance not.the best time they tend to catch people is between 12am and 6am .any car found without any of the above 3 will be clamped straight away and a notice put on your car saying why it's been clamped.so even if a genuine mistake has been made and say your insurance as run out say 20minutes ago they will know straightaway.the reason I said between 12am and 6am most people are in doorz asleep apart from the night workers of course.