With a heritage that harks back to the early Twenties, Jaguar is one of UK's oldest automobile marques still in business. As well being famous for several iconic sports cars such as the XK120, E-type and XK8 along with its many successes in international motorsport, it also has a reputation for producing elegant, luxurious and powerful saloons. These have included the Mk VII, Mk 2 and Mk X, plus eight generations of XJ, all of which set a new standard for their performance, ride and comfort. Launched in 1986, the fourth XJ model internally known by Jaguar as the XJ40 not only had a new and more modern design than its more traditional predecessors but also featured an innovative, and at the time class-leading, specification that included a clever onboard diagnostic system. However, never a car without issues the XJ40's gestation alone took well over a decade its many reliability issues would have a long lasting impact on both its reputation as well as Jaguar itself. AUTHOR: Paul Walton has been a motoring journalist since 1999, starting his career at Classic Cars magazine. He moved to BBC Top Gear in 2002, becoming one of the brand's editors in 2005 responsible for a bi-monthly buying car, a position he held until 2011. After a spell being freelance, when he wrote for a variety of specialists titles including Classic & Sportscar and the Goodwood Festival of Speed programme, in 2012 he became editor of Jaguar World magazine, covering a brand he has admired since his father owned a classic 420G in the Eighties. He has since edited several other titles including Ultimate Supercar, Aston Martin Driver and Classic Mercedes. 164 illustrations