Good news! There is now an AWD version of the flagship saloon, available only with a supercharged 3.0-litre petrol V6 and eight -speed auto ‘box.

While it’s only distinguishable by an AWD boot badge, diffusing power from the 335-horsepower motor across all four wheels has meant an extensive chassis rework, borrowing expertise from sister company Land Rover. Underneath, there’s new front halfshafts, differential, transfer case, modified steering, suspension, subframe and exhaust, as well as extra sound-deadening to stave off transmission whine.

Despite the LR parentage, the Jag system has been conceived to replicate the feel of a rear-drive car, feeding as much as 100% of the power to the back wheels when grip allows. In Winter (one of three modes – the others are Normal and Dynamic), it pulls away in second gear to minimise wheel spin and sends 30% of the power to the front by default. By measuring speed, steering angle and brake pressure, it works out where to put the torque, with the capability of running 100%of it through the front wheels.

This car will massage your buttocks while you’re driving at 45mph down a snow-covered B-road. It’ll lunge up icy hills and wriggle through quick lane-changes that’d trouble some SUVs, and you have to look for the limit to find that the AWD and stability systems are doing most of the work.

But if you’re the sort of XJ-driving man-about-Berkshire that laments resorting to his SUV in the winter, you’ll have to stick with the Range Rover, because it’s only going to left-hand-drive markets.

The XJ wasn’t initially destined for AWD, so the engineers have had to work around an awkward body and engine design – a necessary task, considering AWD models account for almost 50 per cent of the US market for big saloons, and up to around 80 per cent in the Snow Belt states and Canada.

But when it’s only worth around five per cent of the British luxo-barge market, there’s not a strong enough business case for re-engineering it for RHD markets, even despite the rear-thrusting XJ’s, er, bracing proclivities on ice. That’s a terrible shame. Especially for trees.

This story originally appeared in the January 2013 issue of Top Gear magazine.