While there’s no escaping its mass or girth, the GLS doesn’t possess that supertanker-stranded-in-a-duck-pond feel you might expect on UK roads. Its lofty driving position is a key factor here, affording a commanding view that makes the task of placing and then keeping its enormous size within the confines of your lane reasonably easy most of the time – provided said lane is wide enough in the first place.

Around town, this elevated visibility is very useful indeed. It does little to make the GLS any more manoeuvrable in tight car parks or in narrow side streets, mind you – where you really do feel the car’s size, and where, at times, you can’t help wishing Mercedes had considered adding four-wheel steering. But aided by steering that, at 2.8 turns between locks, is not only sensibly geared and precise but also convivially light, the car’s reasonably tidy and responsive handling does at least make the process of navigating the GLS through traffic and around urban junctions a little easier than its sheer size might suggest it should be.

High-riding view makes road placement easier than its size might suggest, while cornering grip levels are commensurate with expectations of a heavyweight luxury SUV

Move up to open-road speeds, however, and while the process of flowing the GLS down a quick road remains reasonably intuitive, the car’s handling doesn’t quite mask its mass as effectively as it might. Steering response becomes notably more leisurely, while the amount of body roll that accompanies a more hurried style of driving begins to feel pronounced. Nevertheless, the steering’s linearity – as well as the subtle sense of elasticity that gradually builds as you wind on lock – ensures that there’s a reassuring sense of steadfast stability and predictability about the car’s limit-handling behaviour.

Grip levels are good if not infallible, and being roughly where you’d expect them to be in a modern 2.6-tonne luxury SUV. Push hard enough and it will be the GLS’s 285-section front tyres that relinquish their purchase first, allowing the chassis to gradually push into gentle understeer, at which point the car’s sympathetically tuned ESC system gracefully steps in to tidy things up so that, as often as not, you might not even notice the line you’ve just crossed.

Assisted driving notes

Mercedes remains in a strong position for the functionality and effective integration of its semi-autonomous driver assistance systems; and because the GLS comes in such a well-equipped specification, it gets the whole lot as standard.

The automatic lane-keeping system has a more guided feel than some, but still requires enough input from you to keep you engaged. Although it doesn’t always work well on single carriageways, it recognises lane markings on dual carriageways consistently – and usually even through roadworks – and its assistance feel can be turned up and down according to preference. The speed limit assist system generally recognises speed limits very consistently, too.

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The intelligent cruise control is one clearly tuned primarily for the North American market, so it doesn’t guard against undertaking a slower-moving car; but in busy traffic, that can allow for smoother progress.

Comfort and isolation

In light of all the S-Class limousine references that Mercedes pretty freely makes about this car, you’d expect its engineers to have made damn sure that it performs exceptionally with regards to ride comfort. It was with some disappointment, then, that our testers noted the manner in which the GLS addresses typical British A- and B-road surfaces.

Uneven stretches of country road highlight a tendency for the GLS body control to succumb to pronounced side-to-side jostling, while the car’s secondary ride seems happy to fuss and amplify some of the numerous ruts and edges that it deals with – most noticeably at town speeds. A degree of ride sophistication might well have been sacrificed in order to beef up the Merc’s off-road worthiness, but the similarly capable BMW X7 does notably better to isolate its occupants – and it’s not the only GLS rival you could claim that about. The fact the BMW comes as standard with 21in wheels, as opposed to the larger 22s on the Mercedes, could well be a contributing factor.

Over more uniform undulations, the GLS’s primary ride is at least defined by a likeable pillowy feel. The way its Airmatic suspension works to check vertical movement doesn’t make for as much outright high-speed body control as you might like, which is more than likely a product of its immense weight; but remembering that this is a luxury car, that is at least forgivable.

On smoother motorway surfaces, cabin serenity is good. At a sustained 70mph, our microphone returned a reading of just 62dB – one decibel quieter, believe it or not, than the S350 Bluetec we road tested back in 2013.

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