The car was introduced in September 1968. Power assisted steering and leather upholstery were standard on the 2.8 L 'De Luxe' and 4.2 L models and air conditioning was offered as an optional extra on the 4.2 L. Daimler versions were launched in October 1969, in a series of television advertisements featuring Sir William. In these spots, he referred to the car as "the finest Jaguar ever". In 1972 the option of a long wheel base version, providing a modest increase in leg room for passengers in the back, became available.
The XJ12 version, featuring simplified grille treatment, and powered by a 5.3 L V12 engine (coupled to a Borg Warner Model 12), was launched, also in 1972: 3,235 of these first generation XJ12s were built. Again, an upmarket version, this time called the Daimler Double-Six, was available, reviving the Daimler model name of 1926-1938.
Series 2 (1973–1979)
Normally known simply as the "Series II" (pronounced Series 2), the XJ line was facelifted for 1973. A 3.4L (3442cc/210in³) version of the XK engine was available from 1975. However, the 4.2-litre versions were the biggest sellers in the United Kingdom.
The XJ12 (and Daimler Double-Six) version, with a 5.3 L V12 engine, was again part of the line-up, along with long-wheelbase models (initially badged XJ6L and XJ 12L) and the XJ-C coupé, now considered a collector's item due to its rarity.
These Series II models were known for their poor build quality, which was attributed to Jaguar being part of the British Leyland group, as well as to problems inherent in the design of certain Lucas-sourced components.
Visually, apart from the optional longer wheelbase and available "XJ12" badge, the Series II cars are differentiated by raised front bumpers to meet US crash safety regulations, which necessitated a smaller grille, complemented by a discrete additional inlet directly below the bumper. The interior received a substantial update, including simplified heating and a/c systems to address criticisms of the complex and not very effective Series I system. 91,227 were produced, 14,226 of them with the V12 engine.