It’s a very busy time over at Jaguar, what with the F-Type Roadster now prowling the streets and the just-announced Coupe version ready to do the same. There’s the high performance XJR to come too, but it’s the more mainstream models that are relevant to most of us - which is why the XF is so important.

Jaguar has given the XF a few key updates for 2014 and, reflecting the times we live in, the most important change is the introduction of a more frugal new diesel engine. The 2.2-litre four-cylinder unit improves on the previous version with impressive figures of 129g/km of CO2 and 57.7mpg, the kind of numbers that appeal to your wallet rather than your heart.

Part of the reason for the improvement is some clever techy stuff in the shape of a revised cooling system and a bigger EGR valve, but what makes greater sense to you and me is the stop-start system that cuts the engine out when not needed.

If you’ve not experienced stop-start before it might feel a bit weird, but once you trust that the engine will start again the instant you release the brake pedal it becomes second nature. It all helps eke out a few more miles per gallon, and it’s clever in other ways too - pull up and put the transmission in Park and it goes into stop mode, but release your seat belt and it knows you’re home and switches off completely.

You still get the XF’s bit of theatre when you start up, as the air vents glide electrically open and the previously-flush circular gearlever rises up from between the seats. The gearbox is also a new addition, with eight forward ratios.

Despite appearing focussed on economy, the XF still offers a driving experience that’s a cut above the norm.

Whether the speed is high or low it remains poised, filtering out bumps so you’re aware of them, but no discomfort is caused. Yet the flip side of this is that when you start to press on, the XF is every inch the sports saloon, gripping strongly and staying level and controlled through corners.

The 2.2 Diesel XF is as economical and easy to live with as a fairly humble family hatchback, yet gives you so much more in terms of comfort, style and driving pleasure.