The country that brought the world some its finest vodkas may soon sell cars that won't start if you've had one drink too many for the road.

Swedish car company Saab said on Thursday that it was considering offering with its cars a key fob with a built-in breath analyser the size of a pin-head that would shut down the engine if the driver had more to drink than the legal limit.

The "Alcokey" is equipped with a small mouthpiece into which a driver must blow to determine an alcohol level. Saab, a division of General Motors, said the car could sell well in Europe, where company-operated fleet cars were common.

"Those companies will want to put a good, positive face forward to the public and one of the ways that they can do that is to equip their fleet of vehicles with an item like this to ensure that their employees don't drink and drive," a Saab spokesman said.

Alcokey is still under development but could cost about $300 (€247), Saab said.

Some drivers who have had too much to drink could try to fool the analyser by having teetotaller friends blow into it, Saab's spokesman acknowledged. "It's not fool-proof."