The incredible 1937 Type 57S Atalante belonged to the late Dr. Harold Carr, a car enthusiast and collector, and is one of only 17 ever made.
Despite its substantial price tag, the Type 57S may have been picked up for a bargain with initial price estimates at the time of discovery more than doubling the sum at auction.
Built as a special edition model of the standard Type 57, the Type 57S Atalante was lower and more powerful, although remarkably it was not the rarest.
An ever rarer variant of the Type 57 was built by Bugatti, a supercharged Type 57SC which developed up to 149kW of power - of which only two were ever made.
Dr. Carr had passed on the contents of his garage to his nieces and nephews in his will without revealing the treasures which lay inside.
Alongside the rare Bugatti is reported to have been an E-Type Jaguar and vintage Aston Martin.