A rare Bugatti motor car, which has been parked in a garage gathering dust for nearly 50 years, is expected to fetch millions of pounds when it is auctioned next month.

The 1937 Bugatti Type 57S Atalante was left in the lock-up in Newcastle, northeast England, by its owner Harold Carr in 1960 with just 26,000 miles on the clock.

The car, one of only 17 of its kind, remained untouched and was known to only a handful of enthusiasts until the surgeon's death in 2007.

Media reports said it could fetch up to six million pounds when it is auctioned at Bonhams' Retromobile sale in Paris on February 7, which would make it the most expensive car to go under the hammer.

The car was originally owned by the first president of the British Racing Drivers' Club Earl Howe.

"I have known of this Bugatti for a number of years and, like a select group of others, hadn't dared divulge its whereabouts to anyone," James Knight, head of Bonhams' motoring department, said in a statement.

"It is absolutely one of the last great barn discoveries."