Over the last few years there have been a number of claims about big cat sightings in Kent, often accompanied by inexplicably blurry pictures taken with cameras that, presumably, have until that point managed to take pin-sharp images.

I'm delighted to say that I've achieved what many would have imagined impossible and spent a week up close and personal with the biggest cat of them all.

I am, of course, talking about the Jaguar XJ – in this instance the long wheelbase version – which these days is possibly a rarer sight than the lion of Lyminge, the panther of Pluckley or even the tiger of Trottiscliffe.

It might be a rarity, but it doesn't lack for presence. It remains one of the most striking designs in any segment and particularly in comparison with its main opposition from Mercedes' S-Class, BMW's 7 Series and the Audi A8.

It is entirely subjective, of course, but I think the XJ is very good-looking car. Pictures don't really do it justice and it is testament to Ian Callum's forward-thinking design that it looks as fresh now as it did when it appeared seven years ago.

It's undergone a few revisions since then, of course, but they have been of the blink-and-you'll-miss-them variety. The car you, occasionally, see today is almost identical to the original.

It's a very fluid design, with few abrupt changes in direction and very little wasted metal. It's looks lean, taught and planted. The swage line that starts from above the front wheel arches fades towards the centre of the car before re-emerging above the rear arches, emphasising the car's length and giving it a 'waisted' look.

Perhaps the most divisive feature of Callum's design is the 'either you like them or you don't' black clad C-pillars, designed to give the impression that the rear windscreen wraps seamlessly around. I'm open to argument as to whether they achieve that particular goal but I do like them, particularly contrasting against white bodywork.

The rear lights – as distinctive as the rest of the car – are all LED and, according to Jaguar, styled to look like cat's claw marks.

It’s all relative, of course, but extensive use of aluminium – body panels and chassis – helps keep the weight of the XJ LWB down.

The XJ that I'm reviewing gets an additional 125mm between the wheels compared to the standard-length car but, Jaguar claims, the long-wheelbase model's dynamic prowess is equal to that of the regular car.

What it does mean, of course, is that anyone travelling in the back will not bemoan a lack of space. The rear of the cabin is cavernous and passengers, in Autobiography trim which is available only on long wheelbase versions, can enjoy treats such as business tables and an entertainment system with 10.2in displays, as well as individual heated and cooled seats with massage.

Front seat passengers don’t miss out either. There’s ample room for the tallest of drivers, yet the impression from the cockpit-like driver’s seat with its wrap-around console and high transmission tunnel is one of a much smaller, much sportier machine.

The driving position is spot on thanks to the multi-adjustable soft grain perforated leather sports seats and the particularly well shaped and sized steering wheel with gearshift paddles to its rear. It’s hard to find fault with, what is, an ergonomically refined and beautifully crafted interior.

Leather and wood are the dominant materials, putting in an appearance on just about every surface you can lay your hands on. It’s all delightfully tactile, as well as pleasing on the eye. Conventional dials have been replaced with a high resolution digital display. It’s very different to Audi’s all-singing, all-dancing ‘Virtual Cockpit’, but can display valuable information such as manual gear change selection and sat-nav prompts.

The infotainment centre, which for so long lagged far behind the competition, has been updated across the Jaguar/Land Rover stables and is, these days, a much more competitive package. It still falls a little short of the very best, but there’s no longer the feeling that you’re being shortchanged.

Autobiography trim also comes equipped with a magnificent 1,300W Meridian sound system to fill the cavernous cabin with lustrous audio.

Boot volume stands at a class average 520 litres, enough room for a decent amount of luggage.

The 3.0-litre V6 diesel fitted to my test car produces 271bhp and 516lbft of torque. Those figures might appear a little on the low side but in reality you’ll find that it’s more than enough. The sprint to 62mph takes just 6.2 seconds, and that level of forward momentum is enough to pin you back in your seat.

That performance does not come at the sacrifice of refinement. The diesel is audible when you work it hard, but with very few clues that it’s an oil burner, and once you settle down to a cruise, you’re propelled along in a cocoon of hushed indifference.

The engine drives the rear wheels through an eight-speed automatic that’s as smooth as silk. It’s excellent at ensuring the car’s always in the right gear to maximise efficiency and refinement. If economy falls further down your list of priorities you can select Sport mode, which will keep the transmission in-gear for longer and speed up the shifts, but it is at the cost of a little of that smoothness.

You can, of course, use the wheel-mounted paddles to select the gears manually. Set the mode to Dynamic, and the gearbox will hold ratios to the red line.

The ride is sublime. With steel coils at the front and self-levelling air suspension at the rear, for the most part the XJ rides with all the splendid isolation that you would expect from a luxury saloon. It does, perhaps, lack that final touch of finesse that some of its rivals possess, but where the big Jag does impress is with its body control.

It will change direction with a litheness that belies its size, while its suppleness over irregular surfaces and composure at motorway speeds is highly impressive.

The XJ's well modulated brakes are as impressive on the motorway as they are in stop-start traffic, and also deliver impressively short stopping distances.

And that agility, that inherent sportiness, brings me back to the driver’s seat which is, maybe surprisingly in what is a stretched limousine, the place where I’d always want to be. Make no mistake, despite weighing almost two tonnes the XJ, even in long wheelbase spec, is every inch a driver’s car.

The steering is precise, beautifully weighted and quick. Turn into a corner and it will hold its line with balanced neutrality, the rear wheels driving the big saloon through the apex before launching it towards the next bend.

It’s this intoxication combination of luxury saloon and sports car that makes the XJ such a compelling machine. That it’s still as competitive as it is, despite its age, simply makes it even more enticing

Jaguar XJ Autobiography LWB 3.0 V6 300PS

Price: £79,60

As tested: £82,435

Engine: 3.0-litre V6 diesel

Transmission: 8-speed automatic

Max power: 300PS

Max torque: 516lbft

Max speed: 155mph

Acceleration (0-62mph): 6.2sec

Urban: 39.8mpg

Extra urban: 54.3mpg

Combined: 48mpg

Emissions (CO2): 155g/km

For more information visit www.jaguar.co.uk