Following the headlines made by Chris Evan’s recent purchases of classic Ferrari road cars it seems that classic cars are once again becoming a high value investment purchase. A good question to ask then, is which is the most valuable car in the world? Happily Octane magazine have sought to answer that question for us and have come to the conclusion that it is a Mercedes-Benz 300 SLR, number 722.

Why should this particular car be the regarded as the most valuable and therefore the most important car in the world? In a word, ‘Moss’. Sir Stirling Moss to be precise, and still, in the words of Octane, the most universally admired racing driver ever. Stirling himself has always been quick to point out that 722 is the most famous of all his steeds.

The reason is the awe in which the Mille Miglia road race was held back in the 1950s, and the way in which the Stirling and Denis Jenkinson victory in 1955 captured the public’s imagination. Here was England’s own racing hero beating the Italians at their own game, alongside the deeply eccentric Jenks, bearded and studious, reading pace notes from a glorified toilet roll holder of his own invention, known as the Roller Map.

As for the car itself, it rewrote the rule book. Based on the W196 Grand Prix car, there was little that was conventional. The straight eight engine used desmodromic valve gear (valves are mechanically opened and closed rather than simply using springs to close them, for improved precision) and fuel injection (a relatively new technology at the time). Drive was taken from the centre of the crankshaft via a gear, rather than from the end; massive drum brakes were fitted inboard and, for Le Mans, were supplemented by a clever air-brake arrangement; and the rear suspension was an unusual version of the swing axle, less prone to the ‘jacking up’ problems that typical swing axles suffer. The bodywork was produced in the ultra-lightweight Elektron magnesium alloy, also famously used on the 1935 Bugatti Aerolithe Paris show car.

Sadly it was a 300 SLR that Pierre Levegh was driving when he careered into the crowd at the 1955 Le Mans, prompting Mercedes-Benz’s withdrawal not just from the race but also from international motor sport as a whole including Formula 1. The Silver Arrows as they were known back then have only just returned to Formula 1 this year with a certain Michael Schumacher driving for them. Had the accident not occurred, a SLR would almost certainly have won or been podium-placed with Stirling and Fangio at the wheel.

As for 722, after an active life it is now in semi-retirement at the new Mercedes-Benz museum, following a comprehensive rebuild and a last drive, with Stirling poignantly signing the bonnet “We did it together..”. Ironically, its race success and its worldwide exposure at historic events around the world have turned it into a car of such extreme high value that Mercedes-Benz is reluctant to use it in anger again.

Oh, and the value, a very cool £40,000,000.

Click the link below to read about the Octane’s top 25 most valuable cars in the world including Jim Clarks Lotus Type 25, the Jaguar D-Type and the Ferrari 250GTO