“Life could never be
  a drag with this
  thoroughly modern,
  all-aluminium Jag!”

YOU COULD SAY that Jaguar has 'seen the light'. Its all-new flagship saloon uses aluminium for a lightweight construction that endows it with both performance and economy benefits as well as a nimbleness that belies its size. Unlike Audi, Jaguar has opted for unitary construction. The complete monocoque is fabricated from aluminium bonded and welded together like the fuselage of an aeroplane to form an extremely strong yet light bodyshell.

The range starts with a 240bhp 3.0-litre V6, moves on to a new 3.5 V8, then a normally-aspirated 4.2 V8 with 300bhp. At the top is the supercharged 400bhp 4.2 V8 XJR. Having sampled all models in the range a few months ago, we decided to test the middle-of-the-range 262bhp 3.5 V8 SE.

Distinguished lines give the new XJ a unique identity that proudly stands out from its German rivals. Detailing is subtle. Check out the neat integration of indicator and repeaters in the chrome bumper inserts and side rubbing strips; the neat approach lights fitted into the underside of the door mirrors; the shapely and pleasant-to-the-touch chromed door handles.

Drivers really do get the best of it in the new Jaguar. For a start the
XJ goes beyond any of its rivals to ensure that the perfect driving position is not only attainable, but easily so. Not only is the power seat adjustable in all the usual planes, but you can also adjust the length of the seat cushion to maximise under-thigh support (essential on long journeys). The leather and burr walnut steering wheel adjusts electrically (of course) for rake as well as reach but the XJ's real trump card is the adjustable pedal assembly. Twist a switch and the pedals can be moved closer or further away from the driver's feet.

Another essential 'toy' is the 7-inch touch-screen set-up (optional on the 3.5). This is by far the most friendly and easy to use system currently available. Everything, from audio, telephone and climate control to navigation, is just a soft fingertip touch away. You can also opt for voice control for those times when your finger just can't be bothered to do the walking.

Other sought-after kit fitted as standard includes an electronic park brake (you can't really call it a 'hand' brake anymore) that releases automatically as you pull away, central locking that locks the moment you select a gear, cruise control, power fold-back mirrors, self-locking boot, on-board computer, rain-sensing wipers, auto lighting and three memory settings for just about every physical setting a driver would wish to personalise.

One particularly likeable aspect of the Jaguar is that most of its technology is out of sight. For example, the XJ's air suspension doesn't need your input when it comes to selecting its settings. It just picks the best one for the job and gets on with it. Consequently the cabin's ergonomics are uncluttered so you never feel overwhelmed by the number of functions or button. All are easily identified, large and easy to use on the move. Now you are free to do the most important job — the driving.

Not only is there a lot of space for the driver and every passenger — there'd be no complaints from four adults travelling the length of the British Isles — but Jaguar make getting in and out easier. An 'easy-exit' facility simultaneously raises the steering wheel to it highest point and lowers and slides back the driver's seat for easier entry and exit. And, in spite of the space, the cockpit seems to wrap itself around you in a way that makes you feel you are 'in' the car and part of it, not just perched on its seat. That impression is accentuated by the XJ's high waist.

While the slim windows help to mask the size of the XJ, visibility out remains good. Further aiding visibility are well-sized polychromatic door mirrors that dim automatically in tandem with the rear view mirror. Automatic front and rear parking sensors let you know about the parts you cannot see. Funnily enough, once you've driven a car with them fitted you'll wonder how on earth you managed before.

Within minutes of getting behind the wheel we realised this was special. Not only does the 3.5 V8 put down a lot of power, but the creamily smooth six-speed automatic transmission is a treat. So much so that while you're driving a 3.5 you never for one minute feel you've been shortchanged by not having the 4.2. Until, maybe, you drive the supercharged XJR!

The new breed of XJs are as much driver's cars as they are luxury cruisers. Show the XJ a sweeping cross-country route and the agile new Jaguar will show you a good time. On paper it leaps off the line to reach 60mph in 7.3 seconds — in the flesh it feels faster. It corners faithfully and accelerates eagerly, surprising you with the tenacity of its grip. Body control is a practical balance between ride comfort and handling ability, while the communicative steering is confidence-inspiring, weighting up nicely as you put your foot down.

All models feature self-levelling air suspension and Jaguar's computerised adaptive damping (CATS) which maintains a firm check on body roll, keeping the car flatter through the twists and turns. Customers can order their car in either SE or Sport guise but the V8 3.5 only comes in SE spec. Choose the Sport package and you lose chrome but gain sports seats and lowered, firmer suspension.

Brakes are competent — with ABS and Emergency Brake Assist — and there's plenty of grip available from the 235/50 ZR18 Pirelli P600s in both the wet and the dry. The well-mannered XJ lets you know in good time when you're approaching the limit before politely stepping in to tidy things up with the Dynamic Stability Control.

Press on drivers will enjoy playing in the manual mode. Third and fourth are especially entertaining — more so with Sport mode engaged. However, you can have equally as much fun leaving the excellent ZF 'box in Drive and enjoy Sport's ability to make compelling use of every last pound of the 3.5's substantial 254lb ft of torque.

As stirring as it can undoubtedly be to drive, the new Jaguar XJ has another side — that of luxury saloon. Flick the familiar J-gate lever into Drive for fully automatic operation and it will acquaint you with the 'W' word: Waftability.

The XJ's less urgent progress is a salve to the pressures of the outside world, transporting you from A to B with smooth, time-defying progress. Cossetted in deep, comfortable leather seats surrounded by the traditional trappings of luxury such as premium audio equipment, lashings of traditional polished wood, thick carpets, chrome highlights, and dual-zone climate control. And some quality silence.

Front seat occupants get comfy 16-way adjustable seats with variable heating, but would be almost as happy to travel in the rear, thanks to a well-shaped rear bench and substantial rear central armrest and loads of headroom. A near-silent, electric rear sunblind also comes as standard. Jaguar buyers have always expected grace, pace and space. With the new XJ, they've most definitely got it.

The rear of the new XJ can be a particularly alluring place to be — not least for children — if you specify the optional multi-media system. Operated via a command module that folds up from the centre armrest, it offers a variety of entertainment from radio, mini-disc and CD to TV, video games and DVD movies. LCD screens are fitted in the rear of both front headrests. Even better are the headphones for the rear compartment's entertainment system that ensure that those sitting up front can't be disturbed by what's going on behind.

And behind the rear seats is more good news: the deeper boot, almost thirty per cent bigger than that of its predecessor, it holds 470 litres of luggage. I wonder many bags of golf clubs that represents…

It goes without saying that as well as pampering its passengers the XJ also has their best interests at heart should the worst happen. Jaguar's Advanced Restraint Technology System provides tailored protection best suited for the severity of a front impact and most appropriate to the individual occupants. The XJ's side thorax and full-length side curtain bag provide protection in a side impact. The front seats also feature an anti-whiplash design.

At speed — something the 3.5 has a hunger for — and surging towards the horizon at the least encouragement by your right foot the Jaguar is a calm place to be, with 90mph requiring just 2,200rpm. Top speed is a continent-crossing 150mph.

Most customers happy to spend getting on for £50,000 on a car today aren't going to be overly concerned about fuel consumption, although the green part of their conscience may like to know that with an XJ they're not guzzling the world's fuel reserves at too alarming a rate. Overall we recorded 23mpg against Jaguar's figure of 26.5mpg. But, as usual, we weren't hanging around. And there were times when the computer was recording figures closer to the official ones of 17.8mpg Urban and 36.7mpg Extra Urban. Don't stray far from the legal limit and the 18.7-gallon tank should be good for a realistic range of at least 550 miles.

Once, not so very long ago, the German marques appeared to offer it all. At a stroke the new XJ has changed all that, meeting its traditional rivals head-on. We all want to be 'the cat that's got the cream', but in this case the Cat is the cream.

Jaguar XJ8 3.5 SE | £49,950 Maximum speed: 150mph | 0-60mph: 7.3 seconds Overall test MPG: 23mpg | Power: 262bhp | Torque: 254lb ft Visit Jaguar's website