Heaven forbid, don't let us mislead you; there's no button adorning the XF-R's transmission tunnel with 'power slide' embossed into it, but it is absolutely true that this is the most mentalist Jaguar saloon ever, and it does indeed have a setting specific to unleashing some deliciously easy and heroic power oversteer. Nice.

From a brand more synonymous with tweed and retired scrap dealers over the last couple of decades, the XF-R will be yet another watershed moment for Jaguar when it hits showrooms in March as a genuine alternative to Germany's dominant triumvirate.

The new XF-R is powered by a 5.0-litre supercharged V8, which is entirely new from the ground up. The current 4.2-litre Jag V8 has been in service for 12 years now, in which time over 600,000 of them have left Gaydon - so it was time for a change. The new unit develops 503bhp and 461lb.ft of torque, but Jaguar has spent most of its time making sure that the low-rev response is instant - because let's face it, even the buyers of super saloons rarely get close to the rev limiter.

As such, peak torque comes at just 2,500rpm, with a significant twist of it building up well before that. The 0-60mph sprint is thus despatched in just 4.7 seconds - exactly the same as a BMW M5's 0-62mph time. Yet, for the other important benchmarks the XF boasts numbers superior to the Bavarian's. So, fuel economy of 22.5mpg plays 19.6mpg, 292g/km of CO₂ plays 344g/km and the Jag should undercut the Beemer's sticker price by around £5,000, starting at about £60,000.

The XF's chassis has undergone some fettling too, with a completely overhauled drivetrain, including an adaptive chassis, stiffer springs and a quicker steering rack than the standard car. Electronic damping constantly monitors the undulations of the road so that grip and comfort are maximised, depending on conditions. The system can actually predict the movement of the car's body based on steering, braking and throttle input, and then adjust itself accordingly to keep things nice and stable.

Control of the adaptive chassis is via the circular 'JaguarDrive' dial on the transmission tunnel, and is three-way switchable between Standard, Winter and Dynamic modes. Of course it's the latter we're most interested in, which when selected holds the gears at higher revs, re-maps the throttle response and torque delivery more aggressively, and alters the snarly engine and exhaust notes filtering into the cabin. Some might be disappointed to learn that the supercharger whine has been deliberately engineered out, though. The suspension gets stiffened too, and the damping rates altered for more grip and feel.

And now for the power slide bit. The XF-R has a new electronic active differential, which is mounted using a four-point system that fundamentally improves the ride quality for a start. It's also a true electronic diff that distributes power to the wheels based on driver input and driving conditions, rather than using the brakes to achieve better grip. Jaguar's engineers have set it up so that in dynamic mode, with the DSC traction control turned off, delightful power oversteer is easily achievable from the rear-drive saloon. We like.

Just look at it, too. We won't bother describing what you're seeing in too much detail because, let's be honest, it's quite plain what Ian Callum has done. Those quad tailpipes look good though, don't they? But it's largely pretty standard sports saloon stuff: deep front chin, bonnet louvres, body kit, new sports seats, a dark and moody range of unique interior trims... you get the picture.

And there you have it; Jaguar's magnum opus now has a mentalist daddy in the family. Obviously a car's worth is a fairly pragmatic affair, so whether it really can wrestle the super saloon crown from the Germans we'll have to wait and see, but it bodes well, doesn't it?

Mark Nichol - 12 Jan 2009