However, what is not so widely known is that the 'XJ4' project (experimental Jaguar, no significance to the '4') started out as a programme to replace the E-Type coupe and roadster with a four-seater, two-door GT, specifically aimed at the American market. But when it became clear that what the company - which had been merged into British Leyland in 1968 - really needed was a modern saloon, the front and rear ends of the prototype were cut off and two more doors added, its coupe-like lines nonetheless still echoed in the graceful shape.

Fitted with either the well-proven 4235cc straight-six engine from the XK sports range, or a new 2.8-litre, six-cylinder unit, the XJ6 made its debut costing from just £2,800. The basic 2.8 model (142 bhp) wasn't the fastest saloon around - it had a maximum speed of 117 mph and accelerated from 0-60 mph in 11.3 seconds - and it had a habit of blowing up, too, but the 4235cc version (245 bhp) had entirely respectable performance, doing 124 mph and 0-60 in 8.8 seconds. With the E-Type's clever independent rear suspension, it handled well, too, even if the over-light power steering made it a bit boat-like to conduct at speed. But what really distinguished the XJ was its refinement - there was virtually no wind noise from its door frames - and its smooth and smotheringly quiet ride, which even today, few cars can match. Strange for us to see now that features such as electric windows, air conditioning and an automatic gearbox (a three-speed Borg-Warner transmission) were only on the options list, and that the standard manual gearbox was only a four-speeder with optional overdrive.