Juan Manuel Fangio's historic Mercedes-Benz up for auction
The car features a 2.5-litre straight-8 engine and technology that was trail-blazing at the time, including fuel-injection, a lightweight chassis and all-round inboard-mounted brakes that out-performed anything released previously.
Bonhams Goodwood Festival of Speed auction will offer the iconic Mercedes-Benz as the double-Grand Prix-winning car in which Fangio clinched the second of his long-standing record five Drivers' World Championship titles.
Bonhams chairman Robert Brooks said: "This is my fifth decade in the business and it was the most exciting discovery that I've made."
Brooks would not reveal the whereabouts of the astonishing warehouse find but he does expect the car to fetch a massive £5 million and he hopes it will one day be driven again.
Speaking to Sky News, racing historian Doug Nye said: "The first time I saw this car I needed oxygen. It's landmark technology and it was driven by a landmark driver."
"What's so special about it is that it has this wonderful, untouched patina," Mr Nye added.
"Some people think it looks grotty - that's not the point - the really rare cars today are the unrestored ones.
"Every car that's restored has lost a part of its history because it's been obliterated by repainting or by rebuilding. Nothing's been obliterated on this, it's just a beautiful survivor."
Potential owners will have to head to the Goodwood Festival of Speed on Friday July 12 armed with a bulging bank balance if they hope to secure this rare offering.