When it comes to a large automobile, they don’t get much bigger or finer than the Mercedes GLS 350d 4MATIC, which makes some yachts look small. Charles Rangeley-Wilson tried one out.

As David Byrne famously intoned in his existential ditty Once in a Lifetime, one day ‘you may find yourself behind the wheel of a large automobile’. You may even find yourself behind the wheel of a large automobile behind which is a large horse box or a speedboat, but that wouldn’t have scanned so well.

It is true, however. One day, you will, and that large automobile may also one day be full of variations on the themes of children, children’s friends, luggage, food, dogs, guns, fishing rods, furniture, Christmas trees and so on.

Then, one day, it may just be you and the dog and the fishing rods. You’ll know when your children have grown up and would rather be in Greece with their mates than in Scotland with you and the midges because you’ll find yourself behind the wheel of a large empty automobile wondering about getting a Lotus instead.

One day. Between now and then, however, a large automobile may be just what you need.

Thus dear reader, this peruser of the horseless carriage is able to reveal to you the identity of the ‘large automobile’ sine qua non. They don’t get much bigger, nor, in fact, more bewilderingly capable than the Mercedes GLS.

Mercedes GLS 350d 4MATIC

I picked this Rubenesque Brunhilda for a spin because I’ve tried other seven-seaters that I found frustratingly unconvincing: great as five-seaters, but teddy-bear room only in the back row and the boot frustratingly small… to boot.

Not with the GLS. The GLS is vast. At 2½ tons and 17ft long, it makes some yachts look small, but that’s the point – if you want a seven-seat car, you might as well buy one with actual room for the seats. Here’s the thing, the back row of the GLS can fit real people! It takes six-footers in comfort and the space behind them, even in seven-seat format, will still take a tolerable amount of luggage: about 300 litres, compared with 680 in two-row format and a cavernous 2,300 litres with both back rows folded flat.

The UK GLS is available in two basic specifications, but only drug dealers or the brain-fevered love children of Mad Max and Liberace would even look twice at the megalodon-on-steroids that is the AMG version: 585bhp and a 0–60 time of 4.6 seconds make it great for Top Trumps, but, otherwise, it’s loco. Opt instead for the silkier charms of the ‘ordinary’ three-litre diesel. On a long round trip to Derbyshire and Cumbria, I never once felt that I needed more power.

For such a hefty machine, the handling is surprisingly tidy. Merc’s standard Airmatic suspension is notoriously good. The review car was also fitted with the Active Curve System option, which uses adaptive anti-roll bars to flatten out the body roll in corners. Whatever was going on down there, it kept everything shipshape and the ride over bumps was boulevard pliant.

Mercedes GLS 350d 4MATIC

I drove steadily, because that’s how you drive yachts. Up high and cosseted by the imperious luxury of the S class cabin, who wants to get a hustle on anyway?

There are six drive modes, from ‘comfort’ to ‘slippery’ and all ports between. Comfort was just fine 99% of the time. There’s an ‘off-road pack’ that, for £1,985, adds a low-ratio transfer, a central diff-lock and the ability to pump the ride height up by 30mm, 60mm or 90mm. Thus equipped, the GLS has a wading depth of 600mm and can go more or less anywhere.

This car is a bus, a van, a tractor or a limousine depending on what’s going on. Sure, it’s a tad thirsty – the official 37mpg was a way off my 34mpg steady-eddy tour. But hey, it’s more economical than the two cars you’d need to match its range of abilities.

Mercedes GLS 350d 4MATIC: The details

  • Priced from around £70,000 – £82,970 as tested
  • Combined fuel consumption 37.2mpg
  • Power 258bhp
  • 0–60mph 7.8 seconds
  • Top speed 138mph