AS any Jaguar fan will tell you, the thought of a flagship big cat with a diesel engine would once have turned you cold.
But things change so fast in the new car arena that diesel is now the buzzword on the boardroom car park.
The type of people that drive a Jaguar XJ want performance and luxury in a perfect package. They are perhaps the most demanding customers in the marketplace and the competition is intense.
But since being owned by Ford, Jaguar has leapt ahead in technology and pure quality and its diesel range is, without doubt, exceptionally good.
Jaguar oil power is perhaps seen at its best in the XJ6 TDVi Sovereign which brings traditional Jaguar values up to date with surprisingly good fuel economy.
It is certainly amazing how things have progressed since those long lost days of the V12 Sovereign and XJS which were not far off single mpg figures if you drove them with a degree of enthusiasm.
But in an environmentally conscious world the Jaguar six-cylinder diesel does not disappoint in any area. It is fast, accelerates very briskly and has a superb ride.
First impressions count a lot and some features on this XJ just leap out and hit you for six. One is the active cruise control which is so clever and user-friendly that it very quickly becomes an integral part of your everyday driving pattern.
For instance, engage it on an open road, dial in the required speed and relax. On old fashioned cruise controls, you would have to disengage it when approaching slower traffic. With the Jaguar system, radar picks up the slower car and adjusts your speed automatically to maintain a safe gap. It also tells you if someone behind is too close for comfort.
I have tried a similar system on other makes, but the Jaguar set-up is streets ahead.
Also, the XJ is one of those few cars in which I can electronically select and fine tune the perfect driving position for me.
The leather seats in this car are very special and allow driver and passenger to leave the car after a long trip feeling as refreshed and relaxed as when they got in.
Rear seat passengers are in for a treat with individual multi-media screens.
The latest XJ is a perfectly balanced car for its size. Its nimble performance and faultless roadholding make it more than a match for German and Japanese competitors.
Given the fact that it returns 35mpg on the combined cycle, despite its engine having a powerful twin turbocharger this car has a lot going for it. In addition I have to mention the six-speed sequential/auto transmission, which is a dream to use.
But economy does not come at the cost of performance because the XJ diesel is quick off the mark with a 0-62mph sprint of 8.3 seconds and a top speed of 141mph.
For 2007, the XJ range has been considerably enhanced with alloy wheels as standard and much more making this aluminium bodied beauty an even better prospect in the management market.
FAST FACTS
Jaguar XJ TDVi Sovereign
Price: £50,020
Mechanical: 206bhp, 2,722cc, 6cyl diesel engine driving rear wheels via 6spd automatic gearbox
Max speed: 141mph
0-62mph: 8.3 secs
Combined mpg: 35
Insurance group: 15
CO2 emissions: 214g/km
BiK rating: 32%
Warranty: 3yrs/ unlimited mileage, 3yrs paint, 6yrs anti-rust