Not many new cars get as much build-up and anticipation as a new Jaguar, writes Matt Joy.For starters, they come along a lot less often than premium rivals, and in this country there's the hope the next Jag will be so good that it will step out of the shadows of its forebears.

Not many new cars get as much build-up and anticipation as a new Jaguar, writes Matt Joy.

For starters, they come along a lot less often than premium rivals, and in this country there's the hope the next Jag will be so good that it will step out of the shadows of its forebears. For the XJ, that's a sizeable task: the original 1968 XJ Series I defined the sporting luxury template that has been the target for every Jaguar since.

So what of the 2010 XJ? You won't mistake it for anything else for sure. The design is another product of the team led by Ian Callum, and it's immediately obvious that this is no pastiche of the past. There are hints of the original XJ of course, in the slim pillars and the shape of the grille, but the overall shape is something else. Where its key rivals in the segment tread a predictable four-door saloon route, the new XJ is far closer to a four-door coupe.

It is technically a saloon, but the rear window has disguised pillars and flows into the almost hatchback-like tail. There are numerous smart details too, such as the claw-like rear LED lights. It makes its more conservative rivals look positively dull. It also puts it in contention with cars like the Maserati Quattroporte - expensive, exclusive and with a strong sporting flavour.

Step inside and the XJ continues to impress. All versions come with a standard panoramic sunroof - that does give up a little headroom in the name of aesthetics, but the result is worth it. With such a slim window line, the XJ feels snug and solid from the inside, with a high shoulder line leaving you cocooned, but not cramped. There's also plenty of stylish design in there too. The touch-screen system means an uncluttered dashboard that's all the better for it, with the now-standard Jaguar gear selector. It's also a relatively low set dashboard, with a band of wood trim that runs around the base of the windscreen, a design element borrowed from motor launches and something that helps to make it feel special.

You can have all the toys to go with it too. The genius Dual-View screen allows the passenger to watch a DVD or TV while the driver can only see information and the sat-nav display, the seats have the option of heating, ventilation and massage and the top-of-the-range Bowers and Wilkins audio system is truly epic. The XJ aims to make its occupants feel special and comfortable, and it does so in fine style. There's also a long-wheelbase version for extra legroom.

Comfort and luxury is only half the story however, because the blood of a sports car runs through every true Jaguar saloon. As with the previous generation, this XJ has an aluminium structure - 50pc recycled too - which gives it a weight advantage over rivals, Jaguar claims as much as 150kg, and that's good for economy and performance. The most popular 3.0-litre V6 diesel version can achieve a very impressive 40mpg and 184g/km of C02, yet deliver proper performance too, with 155mph and 0-62mph in 6.4 seconds.

Those figures translate to real-world performance. The cabin remains hushed even when the diesel is working hard, and there's a pleasing rasp from the exhaust. The Drive Selector also allows you to switch out of standard mode into dynamic or winter, with adjustments made to steering weight, gearbox mode and suspension stiffness.

Even in standard mode, the ride is firmer than the competition. It can still waft along and insulate you from the worst that the road has to offer, but this is a car you buy because you want to be behind the wheel and not sat in the back. Tweak it into dynamic mode and you can push the XJ hard, with responsive steering and fine balance. It's as good at playing the sports car as it is at pampering you on the way home.

Replacing the XJ was the hardest task for Jaguar. Not because of the brilliance of the last-generation version, great car that it was, but because no XJ has been able to step out of the shadow of the original - until now. This is an XJ for the 21st century that pays no more than a complimentary nod to the past.

JAGUAR XJ 3.0 V6 DIESEL LUXURY

PRICE: �52,500

Engine: 3.0-litre, 275bhp turbo diesel

Transmission: Six-speed automatic driving the rear wheels

Performance: 0-62mph, 6.4 seconds; top speed 155mph,

Economy: 40.1mpg combined

Emissions: 184g/km