The XJ is pivotal to Jaguar's continued success. Not just one of the speakers at the XJ's glittering Saatchi Gallery unveil underlined that, but every single one of them. Ian Callum, Jaguar's Design Director said so, while stating that the new XJ is a return to the lithe, beautiful cars that the firm is famous for. Talking us around the car Callum described its "raptor-eyes" headlamps, a visual signature that he hopes will mean people get out of your way when you see the XJ approaching in your rear-view mirror.

On the plinth at the Saatchi gallery the XJ is striking, the big saloon a radical departure for the brand that's quickly re-inventing its design language. The front is a little reminiscent of Maserati's Quattroporte, the confident, upright grille framed by those reptilian eyes and topped by a bonnet bulge that Callum claims harks back to the original XJ.

That bulge is not the only detail that's been plundered from the back catalogue. The new XJ's rear lights within which Callum highlights three "cats claws" lines are apparently related to early XJ tail lights. Whether that's the case is debateable, but what is clear is that whether raiding its history or not Jaguar is clear in its goal of producing modern-looking cars rather than pastiche, homage designs that have until recently been the firm's signature.

The first car to really move things on was the XF, Jaguar's UK MD Geoff Cousins pointing out that even in the current tough trading conditions the XF is performing well - helping the firm ride out the downward sales trend. The XJ should help here too, Jaguar's new luxury flagship hoping to repeat the XF's success against its own rivals, cars like the BMW 7 Series, Mercedes-Benz S-Class and Audi A8.

Several things should help it do so. Jaguar has invested heavily in new technology for the XJ. The interior mixes its traditional hand-crafted feel with beautiful detailing and innovative means of controlling and viewing the instrumentation and infotainment systems. Dubbed iTech, the XJ features a virtual instrument panel that can display a number of driver-selected displays, from navigation to what track is playing on the audio system. It is controlled by voice 'say what you see' commands, steering wheel-mounted buttons or via the central medial hub.

The XJ's environmental credentials should help too, the aluminium construction meaning it weighs little more than its smaller XF relative, which is to the benefit of not just economy but performance too. This duality runs to the core of the XJ, Andy Dobson, the XJ's Chief Engineer, stating that it will provide luxury car levels of refinement and comfort yet still perform and handle like a Jaguar should.

On sale now, with deliveries starting early in 2010, the XJ will be offered with three engines - all familiar to Jaguar's existing line-up. The 3.0-litre V6 turbodiesel represents the entry point, it allowing the XJ to reach 62mph in just six seconds and return an impressive 40.1mpg on the combined cycle. It makes the naturally aspirated 5.0-litre V8 look pointless, it only shaving 0.6 seconds from the diesel's 0-62mph time, yet managing just 24.8mpg. Heading the range is a supercharged 5.0-litre V8 with 470bhp and a 4.7-second 0-62mph time.

Three trim levels will be offered in a line-up that starts at £52,500, each model offered in standard or long wheelbase, the latter with an extra 128mm rear legroom. It looks better in this guise too, the premium for that extra space and longer look coming in at £3,000. You'll be seeing a lot of both models, Jaguar ramping up its marketing activity in the coming months, undertaking numerous VIP events like its London unveil and even taking over all the advertising in London Heathrow's Terminal 5 for an entire month.

The proof though will be in its sales, and its ability on the road. Car Enthusiast expects to get behind the wheel this November for an early drive. Only then will we be able to say with any conviction whether Jaguar's new XJ has got what it takes to rival the best in the luxury car market.