Mercedes GL420 CDI

While the GL drives well on and off-road, has a great diesel engine and lots of presence, it’s too big and pricey. Unless you really need go to off-roading with seven people on board, you should look elsewhere.

There are big 4x4s, and then there’s the new Mer­cedes GL-Class. Measuring considerably more than five metres, it’s even longer than Audi’s Q7 and weighs over 2,500kg. It’s designed for the US, but can the seven-seater make sense here, too?

With boxy, angular lines, there’s no hiding the bulk. Yet despite its size, there’s less space inside than you might expect, with surprisingly tight legroom in the second row of seats. However, the GL’s trump card is its third row, which can be raised or lowered at the touch of a switch, and can easily accommodate two six-footers.

On the move, the 4.0-litre V8 turbo­diesel is gutsy and refined, covering 0-60mph in 7.6 seconds and cruising almost silently on motorways.

Fuel economy is a dismal 23.9mpg, though, and the seven-speed auto box is jerky at low speed. Off-road, however, the GL is highly capable, thanks to air-suspension, hill descent control and a low-ratio gearbox with differential locks. On tarmac, it steamrollers over bumps with ease.

The GL isn’t cheap and, with just a few optional extras, it’s easy to spend a lot of money. Our car had leather seats, adaptive xenon headlights and an elec­tric sunroof, bringing its price close to £70,000. If you want a large and versatile Merc, look at the M-Class 4x4 or the R-Class MPV. At less than £40,000, either makes much more sense.