Mercedes-Benz’s apparent quest to cover every possible market niche continues with the introduction of the mighty R-class.

Described as a Grand Sports Tourer, this vehicle may just be the solution to a problem that doesn’t exist.

The proposition is this: a luxury blend of MPV, SUV and estate, which also offers a dynamic driving experience. Sounds like a tall order.

Well, on the face of it, the R-class ticks many of these boxes. Available in either 4.9m standard wheelbase, or 5.15m long wheelbase form, and with permanent four-wheel drive, the new six-seater certainly satisfies the size and versatility criterion of both SUV and MPV.

But in short wheelbase guise, access to the rear row of seats is an ungraceful affair and best left to nimble children. So the £1,500 premium the long wheelbase commands may well be worth investing in.

Three engine variants are available in the model line-up. The R320 CDI V6 CDI diesel unit produces 224bhp, 376lb ft and returns 30.4mpg combined.

The R350 V6 petrol offers 272bhp, 258lb ft and 24.8mpg, while the R500 V8 petrol produces 306bhp, 339lb ft and returns 21.2mpg. A 6.3-litre AMG-tuned R500 is due later in the year, as is a 2.8-litre diesel.

These engines, all allied to seven-speed 7G-Tronic gearboxes, should help deliver unhurried, stately progress, with the option of muscular acceleration when needed.

In reality, the R320 CDI tested, expected to be the best seller in the range, is uninspiring and harsh at high revs.

Naturally, the 5.0-litre V8 petrol offering has no shortage of grunt, and can usher the big R around sedately or with urgency. But then it does cost £49,990 to the R350’s £38,475.

Mercedes is expecting to sell just 1,800 units annually in the UK, with the US accounting for a far greater percentage of total sales. And this is a market where the R Class will make perfect sense.

In Europe it just feels a bit unnecessary, but given its undoubted ability to eat up countless miles of bland American highway, it should go down a storm on the other side of the Atlantic.

Price: £38,470-51,490 (£51,490 for LWB)
Engine: 3.0-litre V6 diesel, 3.5-litre V6 petrol, 5.0-litre V8 petrol
Performance: 0-62mph: 6.9-8.8sec; top speed: 134-149mph
Transmission: Seven-speed automatic
Efficiency: 21.2-30.4mpg (comb); 246-317g/km CO2
CAP RV: £19,900 (52%) to £23,700 (48%)
Rivals: Porsche Cayenne, BMW X5, Range Rover, Audi Q7, Volvo XC90, Volkswagen Touareg
Strength: Lack of direct competitors, badge credibility
Weakness: Reason for being
Opportunity: To carve a true niche
Threat: Tries to be too many things to too many people