Considering that Rudolph Diesel built the first working model of his oil-burning engine back in 1893, it's hard to believe that some car companies are still only getting around to introducing diesel engines to their ranges 112 years later.
Jaguar has long faced a dilemma over its image. Since the purchase of the British marque by Ford, the pressure to turn a decent profit and win over new younger buyers has been constant, yet the need to protect the tradition and heritage of the brand remained sacrosanct.
The tug-of-war between pushing forward with new models and technology while retaining its roots has led to some interesting results. For one, the Jaguar approach to in-car entertainment technology has created one of the most user-friendly touchscreen systems on the market, far superior to the twist and click menu systems of the German brands.
However, it has also led to some serious delays in adapting to market changes. The most evident is the failure to bring forth diesel models to its range, despite its clear popularity amongst buyers in Europe. In part the delay was driven by Jaguar's obsession with the US market. It saw its future in winning over its uncouth and uncultured American cousins to a bit of British tradition. Yet with the falling dollar and cut-throat competition in the US market, the powers that be seemed to realise that, like it or not, they'd have to deal with their closer Continental cousins. And for them, diesel is a must.
Jaguar previously opted to appeal to younger buyers with new entry level models like the X-Type and mid-range S-Type. These may have saved the brand from extinction, but the lack of diesel simply cut it off from the biggest growing category in the premium market in Europe.
Finally, after much debate, Jaguar opted for a diesel engine in its S-Type two years ago. It was a very safe bet, the S-Type was never going to be one of the mainstays in the market. The result has been as expected: there has been no mass exodus from the brand by the traditionalists and it has opened the door to a host of new customers. Now the bosses at Jaguar feel confident enough to let oil burners feature in the X-Type and XJ ranges. It's about time.
The X-Type features the 2.2-litre turbodiesel unit taken from parent company Ford. It was recently introduced in the Mondeo range - upon which the X-Type is ultimately based - and received a warm welcome from the motoring press. Ford has been pushing the 2.2-litre unit as a sports diesel, and in the X-Type it loses none of its performance characteristics.
Mated to a six-speed manual gearbox in our test car, it offered plenty of pulling power, with a top speed of 220km/h and 0-100km/h time of 8.5 seconds. Fuel consumption averages at 47mpg. And while it puts out 152bhp, of more importance to diesels is the torque on offer, with 360Nm propelling you forward at just 1,800rpm.
The latest X-Type diesel may not match the BMW 320d in terms of outright performance, but Jaguar engineers clearly opted for comfort and silence over raw power.
Far more sensitive to the Jaguar brand is the introduction of diesel to the flagship XJ range. Whatever about the more youthful 30-somethings in their X-Types, the XJ has long been home to the most traditional audience in the Jaguar firmament.
However, five minutes behind the wheel of the diesel XJ only adds to our annoyance with the decision makers at Jaguar. With its thick laminated glass, extra sound-proofing and smooth power delivery, the foremost question is not whether previous XJ owners will buy into the diesel idea, but why the high-paid executives sat on their hands for so long over this.
The 2.7-litre engine is the same unit that features in the S-Type, developed by Ford in partnership with diesel experts at the French PSA Group (the parent company of Peugeot and Citroen). It matches the 3-litre petrol XJ in terms of acceleration, and outstrips all but the supercharged 4.2-litre XJR in terms of torque output.
While 2.7-litres may seem a little tepid in such a big car, the secret to its success is the lightweight aluminium body of the XJ, allowing smaller engines to be used than you'd expect for a car of its size.
Thanks to enormous developments in terms of diesel technology, the days of diesel clatter seeping into the cabin and forcing all inside to shout at one another are long since gone and the XJ diesel is whisper quiet. Even at idle there's little engine noise.
Like the new X-Type, Jaguar has opted for refinement over performance and while there's plenty of power on offer, particularly at motorway speeds, there's a noticeable throttle delay when you move from full automatic to semi-auto and request it to change down a gear. This XJ is built for cruising, munching away at the miles while those inside float along oblivious to the effort involved. Official combined fuel consumption is claimed at 35 mpg, hardly the sort of figures to attract Green party activists onto the forecourts, but respectable nonetheless.
The diesel XJ should see Jaguar sales in Europe rise dramatically, though admittedly from a pretty low base. If, as suggested, prices start just below €90,000, it will have a significant price advantage over all but the Audi A8.
Meanwhile, Jaguar should be doing much better than it is. Dithering over introducing diesel may have cost it years of potential sales in Europe. With luxury sales languishing across the globe, the British brand needs to sharpen its claws if it wants more of the action.