A couple of months ago a Steve Sutcliffe blog on this site went viral and popped up in the national press.

Sutcliffe quoted his mother-in-law, who had heard of a sure fire way of working out what side of the car the fuel filler resided.

Read Steve Sutcliffe's original blog on fuel filler caps

As it happened, her sure-fire rule (that the fuel gauge graphic gave the clue) was not quite as sure fire as it first appeared.

Well, I haven’t got a sure fire way knowing either, but I think I can explain why the filler cap is where it is on your car.

When a car is designed, it usually designed from either a left-hand or right-hand drive point of view. Although it must date back decades, the general rule seems to be that a car’s drivetrain is engineered so the exhaust exits on the opposite side to the pavement.