POWER and grace are qualities normally associated with Jaguar cars but today they come with an added element - economy.

Not so long ago you would be lucky to get 25 to the gallon out of a big Jag, now you can almost triple that thanks to super efficient design and new engine technology.

The new XE sports saloon set the scene with the introduction of Jaguar Land Rover's new Ingenium diesel engine a couple of months ago and now it's time for change with the larger XF.

This is the car that set the ball rolling for Jaguar's revitalised approach to finesse back in 2007 and it has gone on to win more awards than any other model bearing the famous ‘fast cat' marque - 145 of them to be precise.

The new XF will be hitting the scene within weeks and it is smarter than before in every aspect.

In the executive sector it is going to put the cat amongst the pigeons in no uncertain fashion and it is more than a match for anything coming from the three big German brands.

With the Ingenium engine under the bonnet the new XF can lay claim to being the most economical non-hybrid saloon of its kind with an official fuel return of 70.4mpg and emissions of 104g/km.

Those figures are for the lower powered of two versions of the diesel which are being fitted to the new XF developing either 163 or 180ps.

They will power the bulk of Jaguar's new business class saloon which is priced from £32,300 to £49,945 - on par with the current model.

The top end cars are truly sporty and come with a 3.0-litre V6 diesel boosted to 300ps or the supercharged 3.0-litre V6 petrol engine Jaguar also uses in the high performance F-Type coupes and convertibles.

It is a formidable line up and good enough to trouble the likes of the Audi A6, BMW 5 Series and Mercedes E-Class in the executive league.

What the Jaguar brings to the party is a touch of distinction that is British to the core - not to mention the lowest tax ratings, insurance costs and highest residual values of the lot.

The XF is built in Britain at Jaguar's Castle Bromwich factory in Birmingham where the company has recently invested more than £400 million upgrading its high tech aluminium production facilities.

That is on top of a further £500 million which has gone into building a brand new plant in Wolverhampton to make the Ingenium engines.

Lightweight construction is key to the XF's performance and with 75 per cent of the car being aluminium it is significantly lighter and stiffer than rivals.

The new diesel tips the scales at some 1.6 tonnes making it 11 per cent lighter than the previous XF. It is also slightly shorter and lower but with a longer wheelbase there is more room inside, especially in the back.

A shorter front overhang and a more angular body with a pronounced shoulder line and a bold new face with a more upright grille actually makes the car look larger - a stylish illusion if ever there was but one which has made it more aerodynamic.

Different trims - there are four - involve subtle changes to the front bumper while from behind the XF appears more composed with distinctive ‘double roundel' light clusters creating its own signature at night.

Other new features include more pronounced side vents on the front wings, a quarter light in the rear door and a shark fin antenna on the roof. The XF looks all the better, very stylish and contemporary.

Inside, there is noticeably more leg and headroom in the rear with a defined 40/20/40 seating arrangement that incorporates a ski-flap in the centre leading from the good-sized 540 litre boot.

The dashboard now features the sweeping veneered ‘Riva hoop' below the windscreen - first seen on the larger XJ models - while the seats have been remastered to give better support.

In the cockpit, the XF's characteristic welcome sequence of the rising rotary gear selector and the rotation of the air vents on start up stays a feature on automatic versions. The gear selector is now mounted centrally with cup holders behind as opposed to side by side in the previous XF.

The dash also has a new look to accommodate Jaguar's latest touchscreen technology which, by the end of the year, will have entered a new phase of high speed graphics and advanced connectivity.

As such the XF fitted with Jaguar's InControl Touch Pro equipment will be ahead of the game when it comes to in-car infotainment.

The new system will cost from £1,710 and adds a 10-inch central display screen as well as a 12-inch TFT ‘virtual' instrument panel, turning the dashboard into a digital wonderland.

With quad core processors, Ethernet hook-ups and a suite of apps it packs more power than most tablet computers and also includes an embedded SIM card for emergency tracking and the integration of smartphone operations to manage some of the car's functions remotely.

It is high end, sophisticated technology on the go - and so is the engineering under the skin of the new XF.

Like the XE it uses an advanced suspension set up to get the best out of the rear wheel drive powertrain and on the road the XF is very agile.

The car excels with the higher powered engines where 0 to 60 acceleration is close to the five second mark - as demonstrated putting the supercharged model through its paces on a track - yet even the Ingenium models are no slouches.

The 180ps diesel achieves 0 to 60 in 7.7 seconds, tops out at 136mph and is still rated at 65.7mpg with a CO2 figure of 114g/km, although on our drive through the mountains of northern Spain we could only muster an average of 38mpg.

It is surprisingly quiet and refined for a 2.0-litre four cylinder diesel and makes a good fist of powering the XF.

The V6 engines make the XF a sports saloon of the highest order and the diesel has masses of mid-range pull managing 0 to 60 in 5.8 seconds - not far off the 5.1 seconds of the supercharged version.

Both cost the same and the real choice is down to fuel economy which comes back at 51.4mpg for the diesel and 34 to the gallon for the petrol.

Make the most of the multi-mode drive control which can switch the XF into sports mode for the open road or eco settings for city driving and the car is pure enjoyment, so typically Jaguar.

The Ingenium models come either as autos or manuals and to assist in poor conditions Jaguar is fitting the automatics with a special traction system enabling the car to pull away smoothly in slippery conditions.

Make no doubt about it, Jaguar means business with the new XF. It is cutting edge in every aspect and a breath of fresh - and British - air compared to the alternatives.