Jaguar's iconic XJ is turning 40 this year and to mark the occasion the carmaker is organizing a number of celebrations including a classic car Grand Prix run by the Automobile Club of Germany at the Nurburgring. In its checkered history, the flagship saloon has sold around 900,000 units and with an all-new model due in just a couple of years that heritage is set to continue well into the future.

The first XJ was launched in September 1968 and has served as the Jaguar flagship model for most of its production span. The original model was the last Jaguar saloon to have had the input of Sir William Lyons, the company's founder, and it eventually spawned a rebadged version for the Daimler Motor Company.

Until the 1990s the XJ's design remained familiar amongst the model range at Jaguar. The original XJ (which comes from the name 'eXperimental Jaguar') was available with a 2.8L and 4.2L engine, but in 1972 a 5.3L V12 was introduced that gave the XJ a blistering top speed of 149mph making it the fastest sedan in the world at that time.

While the fuel crisis of the ‘70s forced Jaguar to introduce a 3.4L six-cylinder engine, the 1990s saw the re-introduction of a 6.0L V12 and a comeback to the carmaker’s sporting roots.

To celebrate the car’s 40th birthday, Jaguar will be holding a special event at Germany’s Nurburgring, which include a presentation of a 1969 XJ6 Series 1 that once belonged to Sir William Lyons. There will also be a 1972 XJ12 that once belonged to the Queen’s Mother, as well as a debut of the new limited edition 'Portfolio' model.

Look out for our review of the top-of-the-line Jaguar XJ Super V8, coming in the next few weeks.