Those of you who keep a watch on the car industry won't have failed to spot what's happening to the market for luxury 4x4s or, as our transatlantic cousins call them, SUVs (Sports Utility Vehicles). In short, it's splintering asunder. Wind the clock back as recently as 2001 and a Jeep Grand Cherokee was a credible luxury 4x4. Nowadays it's at least two tiers below the most expensive models available. Therefore, a big manufacturer probably needs at least two big, Plush 4x4s to satiate this huge and broad demand. Some car makers twigged quicker than others and started to diversify their brands into these sub niches. Mercedes were one of those quicker on the draw and the GL-Class of luxury 4x4s has caught all of their German rivals on the back foot.

Here's why. Audi never really got a convincing start in this market, their Allroad 4x4 doing moderate business but never really offering the imposing look and feel many SUV drivers demanded. The Q7 is a promising contender but the effort smacks of too little, too late. The market has evolved since Audi first started work on this car and the Ingolstadt company are forced to play catch up. BMW are a little closer to the target, developing a new X5 that will attack the luxury end of the market, leaving the way clear to massage the X3 upmarket too, giving it a two-pronged assault. Mercedes, however, are already there.

Forget about development cycle times, planned obsolescence and all that marketing speak, they're firing on all cylinders as we speak. The M-Class will account for the majority of sales but for the customer who wants something bigger, bluffer and with an altogether badder attitude there's the formidable GL-Class, priced from £51,675. For those who accuse the Germans of having little in the way of a sense of humour, there's even the £125,000 G55 AMG.

Although it wears a German badge, make no mistake that the heart and soul of this car is pure stars and bars. Built in Tuscaloosa, Alabama, the GL is aimed at the well-heeled buyers of New York, California, Washington and Florida, customers who demand a vehicle with the front to face down a Cadillac Escalade or a Lincoln Navigator. Make no mistake, the GL is a serious piece of real estate. It measures 5,088mm from bumper to bumper which is a good deal longer than a Range Rover and dwarfs what looks to be - on a conceptual basis at least - the GL's closest rival, Audi's Q7.

"The Mercedes GL isn't for the shy or retiring"

Mercedes isn't messing about with any modest engines slotted in to provide an eye-catching entry-level price either. The engine line-up in all GL-Class models kicks off with the hugely impressive 224bhp GL320 CDI diesel, an engine that has already seen widespread service across much of the Mercedes Range. Less well known will be its bigger brother the GL420 CDI which, instead of being a V6, is a beefy V8 good for no less than 306bhp. With a maximum torque of 700Nm, this is the engine to choose if you're planning some serious towing duties. Both diesel-powered versions comply with Euro4 emissions rules and feature a maintenance-free diesel particulate filter. If you want petrol-power, there's the impressive 5.5-litre, 388bhp engine in the GL500, as used in the new S-Class. In future, we'll also see a GL450 V8 petrol model with a 4.6-litre engine developing 340bhp, quite some wallop for an 'entry level' petrol powerplant.

All GL-Class engine variants come with the 7G-TRONIC seven-speed automatic transmission with DIRECT SELECT as standard. Renowned as probably the finest automatic 'box on the market, 7G-TRONIC won't have you hankering after a manual. Another factor working in the GL's favour is the comparatively low kerb weight for a vehicle of this size. Thanks to the strong but lightweight monocoque body and excellent aerodynamics (Cd 0.37), the GL-Class claims some very promising fuel efficiency and emissions figures.

As with any such car, much of its appeal will hinge on practical aspects and Mercedes have worked hard to endow the GL with family-friendly features. It's far more spacious inside than their R-Class sports tourer and features a centre-row bench seat with four-way backrest adjustment which is claimed to provide far better seating comfort for up to three passengers. The wider section of the 1/3:2/3 split-folding seat has a folding armrest with cup holder and compartment. The backrests and the cushions can both be folded down, for transporting bulky loads while the divided seat cushion folds forwards in individual sections, then the backrests are folded forwards to create a flat surface level with the load floor at the rear. A newly developed EASY-ENTRY system provides convenient access to the optional third-row individual seats. To use this facility, the narrower backrest section of the bench seat is released and folded forward together with the cushion. If the front passenger seat is in a further back position, it automatically slides forward. When the third-row passengers have taken their seats, the bench seat can be folded back into position and the front passenger seat returns to its original place.

Equipped with the third-row individual seats, the GL-Class is a full-size seven-seater. Either one or both seats can be electrically folded to create a continuously level load floor which, when the centre seat row is folded down as well, extends right the way through to the front seat backs. Customers who do not opt for the seven-seater version get an additional stowage compartment under the load compartment floor. The optional rear-seat entertainment system, comprising two colour monitors with headphone jacks in the back of the front head restraints and a CD/DVD player under the centre bench seat, allows rear-seat passengers in the GL-Class to listen to or watch their own choice of music or films. To extend the entertainment programme even further, external audio/video sources or a games console can be connected to the system. It's a great way of keeping the kids quiet on a long journey.

Although the market for a vehicle of this size is somewhat limited over here, don't be surprised to see Mercedes gnawing into the Range Rover's market share with the GL-Class. It's not only big and clever but is also well built and sports a prestigious badge. A friend is holding out for AMG to get their hands on it but there could well be a worthwhile amount of buyers looking for something spacious and well engineered. One thing's for sure - it can't fail in the US.

TOP 3 GL CLASS DEALS

The results below show the top GL CLASS deals on buyacar

	Mercedes-benz GL Class GL320 CDI 5dr Tip Auto SW Off Road
	ETR	Mthly £869	Saving £10,314	Price £43,296
	Mercedes-benz GL Class GL500 5dr Tip Auto Station wagon Off Road
	ETR	Mthly £1,170	Saving £11,576	Price £56,054
	Mercedes-benz GL Class GL420 CDI 5dr Tip Auto SW Off Road
	ETR	Mthly £1,077	Saving £11,340	Price £53,670

typical 9.45% APR

PCP finance quote over 48 months,  10,000 miles pa,  deposit of £1000