Black

It certainly seems to come off well enough. Seen plenty of ex police cars at auction were the paint looks pretty good. Pity about the interior, though.

One owner two hundred drivers

White has never been common for cars (vans are different, white is a good base for signwriting). Police cars went from black to white to improve visibility. With all the modifications and hard use there would never be much resale value.

via pale blue, don't forget.

IIRC, it was the most popular colour by numbers for a few years.

That'll be why they later changed to silver, then? And now red? Or yellow ;-)

It backfired in that it depressed the value when white became synonymous with an old police car. But since they are no longer white, it's come back into fashion.

Black did go out of fashion, and the police weren't going to pay extra for a special finish on their GP cars, so chose one of the standard ones. The pale blue with white doors of the panda cars being an example.

Red has been CoL colour for quite a while - and nowhere else.

It's probably because the CoL police just simply want to be different to the Met. If the Met went for red (which they won't, to remove confusion with fire), then CoL would probably have every single car in for a colour change to green by the end of the day.

CoL? City of London? Not red. Met use red for Diplomatic Protection Group

The Victoria Crown P71 is one heck of a cool car; many heavy-duty upgrades. Getting rare now that US police is going for SUV.