This rather unusual-looking machine is the new Vauxhall Insignia estate, which made its public debut at the recent Paris show.I had to take a step back when its huge clamshell tailgate automatically opened to reveal a pair of secondary rear light clusters hidden in the boot lining.

But this unusual layout prompted a piece of well buried piece of trivia to come to mind. There’s an obscure EU regulation that requires all of a car’s lights to be visible, even when all the doors and lids are open.

This law is the reason many estates have stacked tail lights, wrapped around the corners of the body and why the old Freelander and Discovery (which had side-hinged tailgates) had the brake and tail lights mounted in the rear bumper.

Further back in time, it's part of the reason front-hinged bonnets, such as those on the old 3-series and 5-series BMWs, were killed off.