Although the XK120 was the fastest, most exotic car that Britain offered in 1948, it came about almost by accident. In 1945, Jaguar Cars offered a range of stylish sedans and tourers, but used bought-in engines. Company founder William Lyons planned a new sedan with a brand new Jaguar-made engine, designed in secret during World War II. This twin-camshaft straight-six was a masterpiece. Flexible and powerful, its basis was a cast-iron block with a seven-bearing crankshaft. On top was an all-alloy crossflow Weslake cylinder head. It had two noisereducing timing chains, and twin 1.75in (4.5cm) SU carburetors. It looked superb with its polished aluminum cam covers, and stove-enameled exhaust manifold. Delays in the sedan’s development meant that Jaguar had no car in which to install its showpiece. So William Lyons hastily constructed a sports car body on a shortened sedan chassis, thinking it might generate publicity and act as a rolling testbed. The result of this was breathtaking: the XK120 was beautifully, classically proportioned and confirmed Lyons’ genius as a stylist. It was fast, too. On a motorway at Jabbeke in Belgium, test driver Ron Sutton achieved 126.5mph (203.5kph), and over 132mph (212kph) with the windshield and hood removed. Jaguar was deluged with orders, but a new problem arose: satisfying demand. Indeed, most production was exported to the US; one rarely saw an XK120 on British roads.