Can the brand’s flagship SUV offer a more versatile S-Class alternative? Alex Grant finds out.

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Sector: Large SUV Price: £78,095 Fuel: 37.2mpg CO2: 199g/km

The SUV, in its many-varied guise, has steadily nibbled away at saloon and estate car volumes for over a decade, presenting a combination of flexibility, fashionable styling and a high driving position that’s proving increasingly attractive for drivers. In the GLS, that same formula is reaching out into the luxury saloon segment.

This might be a new nameplate, but what’s underneath is familiar. It’s a refresh of the GL, the brand’s flagship SUV which has always felt more attuned to North American tastes than European ones. Like the GLA, GLC and GLC, that final letter aligns it to an equivalent mainstream car model. Positioned as an SUV for S-Class buyers, it starts to make a little more sense on this side of the Atlantic.

Make no mistake, this is no urban runaround. At 5.3 metres long and almost 2.2m wide, it’s big enough to overhang the UK’s average parking space and threaten un-folded mirrors on narrow residential roads. But it makes the most of its yeti-like footprint with plentiful interior flexibility on board. So there’s space for seven adults, without those in the third row needing to be contortionists to get comfortable, and five of the seats fold flat.

Aside from the lack of a compartment for the load cover (surely there’s space to build that in somewhere?) it’s actually a very sensibly shaped, very useful SUV, uncompromised by the need to look ‘sporty’. Genuine seven-seat practicality is something that its closest rivals – Bentley’s divisive Bentayga and the sublime Range Rover – can’t match. And, even with seven passengers on board, boot capacity isn’t far off an A-Class.

That ticks the SUV box, but the S-Class links aren’t quite so strong. Unlike the GLA and GLC, the GLS isn’t based on its equivalent saloon car. It’s an extended GLE, and that’s particularly noticeable inside. With its quilted leather and accents of aluminium and wood it’s certainly not an unpleasant place to see out a long journey, but it’s a little too similar to the significantly cheaper GLE inside, and feels a generation behind the S-Class’s large screens and cutting-edge tech.

But it does at least match up on the road. All of the seats are easy to sink into and air suspension is standard, and delivers impeccably thump-free ride quality without the sort of wallowy cornering you might expect a near 2.5-tonne SUV to exhibit when it’s being hustled along.

You can hustle it along, too. The GLS skips the four-cylinder 250 d engine offered in the GLE – hardly a loss for those considering a car at this level – which means the entry point is the 3.0-litre, 258hp, V6 diesel. It’s a perfect fit, too, the cabin is well insulated from the minimal noise it makes hauling the rest of the car up to speed, and there’s plenty of torque for effortless overtaking. Motorway economy in the low to mid 30s to the gallon is impressive for a car this heavy, un-aerodynamic and four-wheel drive, too.

Ultimately, there’s nothing to criticise other than its outward excess. The GLS’s comically huge dimensions make narrow British roads, car parks and toll booths a squeeze, and it lacks the understated elegance of a tastefully-specced Range Rover. But for those who want a cross-breed of S-Class luxuries and SUV adaptability, it ticks all the right boxes

Verdict:

For those who don’t see the size, economy and price as a barrier, the GLS does little wrong. It feels every bit the upsized S-Class, adding impressive practicality into the mix.