It all started with an Atom. It always does. The miracle that spawned a monster. Draw a line through each modern sports car’s lineage and you’ll end up here; under the sweeping bonnet of the Aston Martin Atom, where the automotive equivalent of the Big Bang took place in 1939.

The Aston Martin Atom – surviving as one of the world’s earliest fully running concept cars – was renowned and revered for decades. Avant-garde, lightweight and highly original, this particular 1939-1940 one-off prototype from the legendary British marque is a hugely significant landmark within motoring history.

Gordon Sutherland, Aston’s owner at the time, had the car designed and built by a dedicated design team under engineer Claude Hill. Gordon explained that “The whole point of the Atom was to make the smallest, lightest, enclosed saloon possible”. It combined the performance, roadholding and handling of the finest contemporary sports car with quietness and the comfort of an aerodynamically efficient saloon body, easily modified and economically produced.

The Atom was finished and registered only six weeks after the Dunkirk evacuation in 1940. At a fraught time when park railings, pots and pans were being melted-down to aid the War effort, the Atom was amongst fewer than 750 private cars to be UK registered in the entire year. Today the Atom, taxed and tested, has completed some 250,000 miles. Its discerning ownership – including two distinguished race/rally drivers – has changed only once in the last 49 years, and this unsung little jewel has long been painstakingly conserved and maintained by one enthusiast owner. This is evolution, in the making.

The unique, 75-year-old Aston Martin Atom is to be a star Lot in Bonhams’ Goodwood Festival of Speed Sale on June 27, 2014. For a full listing of upcoming sales, plus details of Bonhams specialist departments go to www.bonhams.com.