LONG wheelbase luxury from Jaguar is moving up a gear with a new top specification Autobiography model joining the XJ range.

In its latest guise the all-aluminium limousine is plusher than ever with quilted leather upholstery, wooden veneer and a rear seat environment fit for any VIP.

Individually adjustable back seats - complete with massaging function - foldaway tables and a pair of high definition screens are just some of the finer points of Jaguar's latest flagship.

Detail such as leather headlining, illuminated stainless steel kickplates and a suite of onboard technology put the new XJ in the highest echelon of automotive sophistication.

The Autobiography treatment - a classification borrowed from Jaguar's high-end sister ships at Range Rover - comes only on the stretched versions of the XJ which at 17.2 feet tip to toe is some five inches longer than the regular model.

It's priced from £80,250 for a 3.0-litre V6 diesel or a cool £100,000 for a supercharged 5.0-litre V8 petrol and that puts them at the top of the Jaguar pecking order.

Yet compared to luxury liners from Audi, Mercedes and Bentley the XJ Autobiography is highly competitive.

On the road it blends performance and refinement in a fashion that has become a trait of the latest generation of Jaguars and it comes with another trick from the Land Rover camp in the form of All Surface Progress Control which endows the rear-wheel-drive XJ with added slow speed traction in slippery conditions.

The XJ Autobiography sits on 20-inch wheels and at the front is distinguished from its regular counterparts with chrome surrounds around the bumper mounted air vents. LED headlights and mesh grilles complete the frontal finish.

From the driver's perspective the 12.3-inch TFT instrument cluster has been given a software tweak enabling it to display full-screen sat nav information while the cockpit itself remains functional and festooned with controls - just as a Jaguar should be.

The V6 diesel in the Autobiography we drove has been upgraded to meet the latest Euro 6 emission regulations and also given a power boost from 275 to 300ps taking 0 to 60 acceleration down to 5.9 seconds but improving fuel economy to a claimed 48mpg with a CO2 output of 155g/km.

It is nicely torquey with excellent mid-range pull delivering a sporty punch if wanted while on the fuel front it will return high 30s without any trouble. Noise levels inside, even under acceleration, are well suppressed taking nothing away from the full limo-experience.

An eight-speed ZF auto box provides a smooth shifting pattern at all speeds even in sport or manual modes while stop/start makes gas-guzzling Jaguars a thing of the past with the car returning an average of 38mpg on our run.

No range topper worth its salt these days can be lacking in onboard connectivity and the Autobiography is fitted with Jaguar's InControl Touch Pro system which not only allows hook ups to iOS and Android devices it also turns the car into a wi-fi hotspot as well as featuring a 1,300 Watt digital sound system.

The additional five inches of leg room in the rear allied to a more than adequate 479 litres of boot space gives the big XJ extra street cred, especially in Jaguar's all-important North American and Chinese markets.

With the sumptuous Autobiography finish it is now a car which, from either the front or the back seats, delights throughout and provides the sort of status demanded at this level.