THE Mercedes SUV range has undergone a renaming process in the past three years with all models apart from the G-Class gaining the GL prefix plus a third letter that reflects which model it sits alongside.

So, in the case of the GLS it's an SUV design with S-Class characteristics.

The GLS is a seven seat, luxurious SUV dripping with high-end features and it absolutely dwarfs most of its rivals.

Weighing just under 2.5 tonnes, the vehicle measures more than 5.1 metres in length, it is almost 2.0 metres wide and you have to literally climb into the cabin of this SUV which is 1.85 metres in height.

Viewed from any angle, the GLS looks muscular and imposing and our AMG Line model boasted lots of AMG-specific body styling along with privacy glass, a panoramic sunroof and LED lights.

The car is very much based on the outgoing GL model but gains a new front end that mirrors the rest of the Mercedes range plus a modernised rear bumper, tail lights and redesigned exhaust pipes. Our car was sitting on 21-inch AMG five twin-spoke alloys.

The luxurious interior boasts a newly designed instrument panel with semi integrated media display, a new three-spoke multi-function steering wheel, a modified centre console with touchpad plus the introduction of some elegant trim along with ambient lighting.

Techno treats are plentiful with the likes of two eight-inch display screens, a DVD player, two sets of rear headphones (so second row passengers can watch a movie), full smartphone integration via Apple CarPlay or Android Auto, a DAB digital radio, a pitch perfect Harman Kardon sound system, full navigation and plenty more besides.

Our car costing £72,090 (£84,690 with options) was powered by a 3.0-litre V6 258ps diesel engine mated to a nine-speed automatic transmission.

It could sprint to 62mph from a standing start in a very swift 7.8 seconds, topped out at 138mph, and according to official figures, it can deliver combined fuel economy of 35.3mpg with carbon emissions of 210g/km.

There are different driving modes called Individual, Sport, Comfort and Snow that alter the way the car handles and the GLS also features Mercedes' 4MATIC all-wheel drive capabilities along with Airmatic air suspension that raises and lowers the ride height according to the terrain.

Despite its substantial dimensions and the large wheels, the GLS feels well balanced and composed with all but the most severe potholes causing any real issues. Hit one of those though and it will sendreverberations through the cabin.

The steering is well weighted and although the driving dynamics are not exactly blisteringly fast, the GLS moves smoothly through the automatic gearbox with a constant stream of power on tap.

It also feels much easier to handle than you would expect considering its size. The driver benefits from superb all-round visibility and all dials, controls and readouts are ideally positioned for ease of use.

The seats are supportive and comfortable with power adjustment and memory settings. They can also be heated to fend off the winter chill.

On country lanes, the road holding was assured with little body sway unless driven really enthusiastically. Then in the town centres, it proved to be deceptively agile. That said, you will need a parking bay the size of a small bus.

Cruising at motorway speeds is where this car really comes into its own. It eats up the miles with ease and barely a sound from the road surface or engine filters into the cabin.

As far as passenger comfort goes, the GLS excels on all counts and the seats in rows two and three can be quickly folded flat or raised via a couple of buttons. Comfort levels are high and even passengers relegated to the rear of the car are treated to a decent amount of space.

The boot is well-sized too with a capacity ranging from 680 to 2,300 litres depending on seating configuration and there's numerous storage compartments scattered throughout the car.

As one would expect from Mercedes, the GLS is packed with state-of-the-art safety kit with the likes of collision prevention assist, a parking pilot with 360-degree camera, attention assist, crosswind assist and lots more besides.

A Driver Assistance package, costing £1,695, was added to our car and that introduced active blind spot assist, active brake assist with cross-traffic function, active lane keep assist, a distance and steering pilot, along with pre-safe plus system.