Jaguar's original 1968 XJ is one of the most significant cars in the company's history, but that significance is double-edged. It was an outstandingly beautiful and capable machine, qualities that are still apparent today; but its very success became a curse. The difficulty of replacing the first-generation XJ meant that it remained in production, albeit in modified Series II and Series III form until 1992, twenty-four years after it first entered production, striking evidence of the soundness of the original design.

Two all-new replacements, the 1986 XJ40 and the 2003 XJ350, were well regarded but struggled to escape the shadow of the glorious predecessor to which their retro designs paid homage. Only with this year's fourth-generation model did Jaguar find the courage to break free of the original car's look, when it finally realised that the best way to repeat the success of the first XJ was to emulate its boldness, not timidly follow its detailed styling cues.

One of the first of the original XJs, PHP 42G, was used by Jaguar's chairman, Sir William Lyons, and is now owned by the Jaguar Daimler Heritage Trust. Every element of the car's instrumentation, switchgear and so on belongs firmly in 1968, and even at the time it would probably have been regarded as traditional or perhaps even old-fashioned. Wood, leather, chrome and hard, black, shiny plastic dominate. And yet the 1968 XJ6 offers a startlingly modern driving experience. The powerful six-cylinder engine provides performance on a par with that of most modern cars, while a combination of the XJ's sophisticated suspension set-up and old high-walled tyres makes for very good ride comfort. The XJ corners with very little roll; the steering, once you get used to the large, thin, hard plastic-rimmed wheel, works well too. Unusually for the time, it is power assisted, and perhaps a little light by today's standards. Only the rather primitive three-speed automatic gearbox really gives away the original XJ's age as a driving machine, though. The 1961 E-Type, a wonderful car introduced only seven years before, feels positively antique by comparison.

An updated version of the first-generation XJ experience is available from specialist firms such as KWE, which remanufactures and subtly modifies the Series III to as-new or even better-than-new standards. And in the new 2010 model, Jaguar itself now finally offers an XJ that provides buyers with something of the glamour and excitement enjoyed by owners of the great 1968 original.

Jaguar XJ6 Series 1 4.2 litre (1968)

Price: £1,797 to £2,398 (XJ6 range – lower price applies to 2.8 litre version)

Top speed: 124 mph

Fuel consumption: no official data in 1968

CO2 emissions: no official data in 1968

Worth considering: 2010 Jaguar XJ, KWE Jaguar XJ Series III

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