Parkers overall rating: 4.5 out of 5 4.5

The supercharged 4.2-litre V8 that powers the XKR is nothing short of extraordinary. Although the non-supercharged version available in the standard XK is no slouch, the XKR gets an additional 120bhp, which brings its 0-62mph time down to 4.9 seconds and its top speed (which is electronically limited) up to 155mph. But it’s the way in which it delivers its power that makes it so enjoyable to drive.

It’s smoother than other cars in this class – such as the BMW M6 and SL500 – and is as refined as you’d expect a Jaguar to be. But, once you put your foot down, the engine opens up with a distinctive howl, and you can tap into immense amounts of pulling power. Mid-range acceleration (between 50 and 70mph) is exceptional, getting between the two speeds in 2.5 seconds, for effortless overtaking.

The six-speed gearbox can be fully automatic or manual. Paddles behind the steering wheel control the manual changes that are near instantaneous and very smooth. A neat touch is the synthesised throttle blip when you knock down two gears – you get the full effect of the 4.2-litre V8. In March 2009 this engine was replaced by a more powerful 5.0-litre V8 (also supercharged) which 510bhp.

It covers the 0-62mph benchmark in just 4.8 seconds and gets a newer six-speed automatic gearbox.

The XKR offers a perfect blend of out-and-out performance and comfort. The body is made from aluminium, which means it's lightweight. The XKR also has uprated active suspension (which adapts to the road surface and how the car is being driven and it adapts to suit those conditions). It's easy to drive around town as the auto gearbox remains smooth at low speeds and all controls are light.

On the motorway, it performs like a grand tourer should. With the adaptive cruise control (it automatically keeps a set distance between you and the car in front) activated, it will cruise serenely - with little input from the driver. But on twisting roads the precise steering and responsive engine really shine, while strong brakes and huge amounts of grip give you plenty of confidence when pressing on.