Fully controlled valve movement was conceived during the earliest days of engine development, but devising a system that worked reliably and was not overly complex took a long time. Desmodromic valve systems are first mentioned in patents in 1896 by Gustav Mees, and in 1907 the Ariès is described as having a V4 engine with "desmodromique" valve actuation, but details are scarce. The 1914 Grand Prix Delage and Nagant (see Pomeroy "Grand Prix Car") used a desmodromic valve system (quite unlike the present day Ducati system).[3]
So it's a really old system so I'm glad someone mentioned a Bristol for sale.
By the way there was one at J30 of the M5 today being loaded on an AA breakdown truck this afternoon about a 70's model I would say with ovalised grille and double headlights in dark blue.
