We’d understand if you happen to be struggling to imagine what a luxury SUV that’s also trying to be a sports coupe might be like to drive. We wondered too. And then wondered some more once we’d looked more closely at the underpinnings of this car. The platform, you see, isn’t quite as cutting edge as the panelwork, borrowed as it is from the brand’s standard GLE large luxury SUV which, if you didn’t know, is the Stuttgart company’s competitor to cars like BMW’s X5. If you need bringing up to date with Mercedes naming conventions, that GLE model is a lightly facelifted version of the old MK3 M-Class, a design that dates back to 2011. In other words, this Coupe must lug around the platform and steelwork of a vehicle that not only pre-dates the current trend for super-lightweight construction but which also was originally designed to tug horseboxes around rather than potentially tackle the Nurburgring. You might very reasonably think that all that rather hobbles this GLE Coupe from the very start as any kind of really sporting machine.

On the road, this GLE Coupe carries a little more weight than its BMW X6 arch-rival thanks to underpinnings sourced from Mercedes’ more conventional GLE SUV model. That’s a little limiting in the base 258bhp 3. 0-litre V6 diesel 350d variant, though even here, there’s decent traction and relatively agile handling for a car this high and heavy. Plus there’s the benefit of a ‘DYNAMIC SELECT’ handling set-up that allows you to tweak steering feel, throttle response, gearshift timings and the settings of the AIRMATIC suspension’s adaptive damping system to suit the way you want to drive.

Things improve significantly though, if you’re able to stretch up to the version we’re trying here, the 367bhp 450 AMG V6 BITURBO petrol model, a variant capable of 62mph in 5. 7s, 31. 7mpg on the combined cycle and 209g/km of CO2. This version’s lighter than its 350d stablemate and comes with a more responsive 40:60-split rear bias for the 4MATIC 4WD system that’s fitted across the GLE Coupe range. Petrol people also get an extra sportier ‘Sport+’ mode for the ‘DYNAMIC SELECT’ system that delivers a brilliant crackling engine soundtrack. And there’s the option, denied to diesel buyers, of a ‘Sports package’ that includes Mercedes’ clever ‘ACTIVE CURVE’ system, this significantly improving ride quality and reducing bodyroll. The ‘ACTIVE CURVE’ set-up comes as standard on the top version of his car, the frantically quick 585bhp V8 BITURBO petrol-powered Mercedes-AMG 63S model.

Up close and personal, you’re certainly given that feeling. Standing over 1. 7m tall, 2m wide and almost 5m in length, this car dwarfs almost everything else on the road and were it to be bearing down behind in your rear view mirror, you’d scuttle over double-quick. The huge gaping air intakes emphasise the upright single-louvred sports grille that’s framed by three-dimensionally-designed all-LED headlamps. Above, the forward-sloping bonnet with its typical Mercedes power domes aims to characterise this car as one of the brand’s sporting models, rather than just another of its SUVs.

From the side, the shape is even more arresting, with the muscular wings and high beltline of a classic sporting GT somehow blended with the large wheelarches and generous ground clearance of an SUV. The wheels themselves are simply enormous, available in a 22-inch size that’s bigger than anything Mercedes has previously used. This rising lower character crease connects them, working with this more sharply-defined upper swage line to add a sense of purpose to a profile that dips dramatically over the rear C-pillar.

At the rear the designers have replicated the style of Mercedes’ exotic S-Class Coupe, with the slim chrome band sitting over three-dimensional LED rear light clusters and a registration plate incorporated into the rear bumper. The way this rear window is rounded off at the top references a look that for generations has characterised large Mercedes coupe models, this feature incongruously blended with SUV touches like the chrome-plated under-ride guard that sits alongside the twin tailpipe exhaust system.

Time to take a seat behind the wheel. Here, much less effort has been made to differentiate this car from its standard, practically-orientated conventional GLE model stablemate, so the dashboard architecture and control layout is much the same. Still, to try and make up for that, the development team sweated over the details. So the superbly comfortable, commandingly-mounted sports seats get AMG bolsters in nappa leather. Plus there are sports pedals finished in brushed stainless steel and the steering wheel is a smaller stitched AMG item with a supercar-style flattened bottom rim and tactile gearshift paddle-shifters.

All well and good. Where you might be expecting problems though, is when it comes to a seat in the rear. As with every other car in the Coupe SUV segment, that sloping rear roofline has to tell somewhere and, sure enough, really tall folk will have to duck a little to avoid it as they enter.

Once inside though, we can’t see too many issues. Yes, a third centre-seated person won’t be especially comfortable, but since this is supposed to be a ‘coupe’, we can’t see too many likely buyers objecting to that.

Time to take a look out back and raise the standard electrically-operated tailgate. One of the biggest advantages this car has over its BMW X6 arch-rival is that it offers you around 15% more bootspace, the 650-litre total only 40-litres less than you’d get in the conventionally boxy standard GLE model.

This is the kind of car that evokes howls of self-righteous indignation from the motoring press. They’ll criticise its weight, its looks and its politically incorrect attitude. Before, of course, going on to fawn over some enormous luxury limousine or thirsty, dirty supercar. It’s all very hypocritical. If you don’t like this car, then fair enough. But don’t moralise about it.

Needless to say, we’re not going to do that here. Would we buy one? Probably not, but we recognise that a small but significant group of users will absolutely love it and having driven this car, we understand why. This is the kind of model Mercedes needs to make – and not only because the luxury SUV Coupe market segment is an increasingly profitable one. People who’ll never buy this car will nonetheless see it as proof that the Three-Pointed Star is changing into a more dynamic, relevant and sporting brand. And the fact that this is happening should surely concern the top brass at BMW and Audi, for ultimately, that’ll affect their bottom line profits.

As for as the GLE Coupe itself, well it’s not the ‘true sports coupe’ that Mercedes promises, but then no car in this sector is. There’s too much size and weight on offer here for that, weight being a particular issue for this design in comparison with its BMW X6 arch-rival. Potential buyers won’t care very much though, for what you do get is more what they’ll be looking for anyway; prodigious power, sumptuous luxury and real overtaking presence. True, an X6 can give you that as well, but with a Mercedes badge on the bonnet, this extreme package carries a bit more credibility. Or, if it makes more sense, you’ll find it easier to get away with parking it outside your company HQ.

True, your CEO might still raise an amused eyebrow, but if you’re the kind of very individual user who’ll want one of these, then you probably won’t mind that for you’ll be someone who shares the confidence that’s apparent in every aspect of this model’s make-up. In years to come, when considering this market segment, we might well forget who got there first and who tagged along. Who knows, we might even forget about SUV-coupes. In the here and now though, here's one of the very finest.