The dusty but intact Bugatti Type 57S Atalante is one of only 17 ever made. It had a top speed of 130 mph (209 kph) at a time when most cars could only go half as fast.
The powerful two-seater car from the heyday of the celebrated Bugatti marquee is expected to be sold for more than 3 million pounds ($4.3 million).
It was hidden away in the garage of an elderly doctor who last used it around 1960. His relatives found it after his death.
British race car driver Earl Howe was the car's first owner.
