Parkers overall rating: 4 out of 5 4.0

The R320 CDI with 224bhp is a refined and willing unit that's well suited to the motorway. However, around town - and with the R-Class's considerable bulk - it can be hard work, feeling unresponsive. Still, it's designed for long-distance cruising, which it copes with admirably thanks to effortless overtaking and decent fuel economy of 30mpg. The 272bhp R350 V6 has a useful turn of speed, with a 0-62mph time of 8.3 seconds and an incredibly smooth and refined nature.

The more powerful 306bhp R500 version has hot-hatch pace with a 0-62mph time of just 6.9 seconds. And it behaves just like a V8 should, with smooth, sophisticated performance and enough engine noise to please the driver, without upsetting passengers. None of the engines feel quite fast as the figures suggest, which is down to their refinement and the fact that the 7G-Tronic seven-speed automatic transmission often selects a gear too high for what is needed.

The R-Class is far from easy to drive around town, especially in long-wheelbase form. Although the steering is light, it feels bulky and its size means it can be daunting to park. However, a sophisticated parking sensor system is fitted to every car which helps. Standard 4MATIC four-wheel drive gives excellent grip in all conditions and is especially useful on wet and slippery roads.

Variable AirMATIC suspension can be changed from normal to Comfort or Sport, depending on the road conditions, while the R280 CDI has conventional coil sprung suspension. As a grand tourer it is superb though, effortlessly soaking up motorway miles with minimal noise or fuss.