“I think the whole thing is crazy. Cars aren’t designed to stand that sort of thing for 24 hours.” That was W.O. Bentley’s reaction when John Duff planned to enter his 3-litre Bentley into the very first Le Mans. By 1924, when Duff’s Bentley came home first, W.O. had changed his view and the ACO’s endurance trial became a prime goal. After two disastrous Le Mans races it came right in spectacular style for 1927 when the battered 3-litre Old No 7 limped away from a spectacular pile-up to snatch an improbable victory. But it was clear that the experimental 4½-litre car, sidelined by the crash, had the speed Bentley needed for next year.

By 1928 Bentley had a guardian angel. Diamond millionaire Woolf Barnato baled out the sinking company and would prove a track hero, too. Race plans centred around boring out the four to 4½ litres, rather than the parallel six-cylinder range. The new 4½ produced 130bhp – and despite Bugatti’s comparing Bentleys to lorries, the race cars for the 1928 Le Mans only weighed around 1.7 tons.

The 16-valve overhead-cam engine apart, the 4½ was relatively conventional, but thanks to W.O.’s railway apprenticeship it was built like a locomotive. Andrew Frankel, Motor Sport’s chief test driver, has raced many of them: “They’re so wonderfully engineered – you could race and then drive home in.” And Bentley had an extra weapon: its cars were raced by wealthy sportsmen who brought to the marque a seductive image of carefree, debonair style: Bentley Boys were kings of the road.