Legshields with integral crash bars formed part of the sidepanels; these were carefully designed to maximise air-flow to the engine although you'd be a brave rider to test their efficiency in modern urban traffic. The half-fairing and screen housed a smaller three-inch Smiths' speedometer; the magnificent 150mph five-inch speedo was gone for good.

Although Philip Vincent felt that the Series-D was his finest design, the motorcycle-buying public greeted the innovative new models with suspicion. The appeal of the Vincent, and the Black Shadow in particular, lay in its ability to out-perform just about every other vehicle on the road, and in the early post-war years there was nothing to compare with it.

Its creator's vision of the Series-D as a luxury touring machine just did not conform to the public's perception of the Vincent as the ultimate sports motorcycle.

The firm lost money on every machine made, and when production ceased in December 1955 just 460 Series-D V-twins had been built, some 200 of which were enclosed models.

This scarcity means that although opinions about the Black Knight and Prince were mixed when they were launched - not helped by poor quality panelling on the show bikes - their values have risen steadily in the half century since their production. Clean examples of whole bikes now sell for around £35,000 to £45,000 ($65,000 in the USA).