EVER wondered just how rigorous a vehicle is tested before it reaches the showrooms? Well, Mercedes has just given us an exclusive behind-the-scenes look at its testing plant prior to the world premiere of the third generation M-Class luxury 4x4.

Experts at the Stuttgart, Germany-based plant showed us different testing procedures that shake, prod, squeeze and shove the components of a new car in every possible direction for hours, days and weeks on end before passing the preliminary stages.

For example, one of the toughest tests any vehicle undergoes in the world is the chassis testing at the centre.

The axles are pummelled for more than a month and undergo thousands of miles under simulator conditions to test their agility, strength and effectiveness.

It was explained that 3,000km worth of testing at the centre is equivalent to 300,000km of everyday driving.

As the units are shaken to reproduce conditions such as deep potholes and extreme off-roading, the shell of the M-Class resembled something on a fast spin in a washing machine. And just as one cycle ends, another begins.

But strength and endurance is just one section of the extensive building programme the vehicle undergoes.

Styling teams in Germany and Italy battle it out to produce the best designs and there can be just one winner. This edge of competitiveness adds to the overall quality - the German team won the M-Class design.

Elsewhere, in San Francisco, 'digital natives' as they like to call themselves, add all the graphics and interface solutions - they are the new technology department.

Next stage is a vital one for a vehicle which is seen primarily as a family model and wants to offer the utmost protection - safety.

The new M-Class is kitted out with some amazing technology with a very strong emphasis on accident prevention.

There is a fatigue recognition device to help detect driver tiredness. This monitors the steering for any behaviour changes.

Then there is night view assist, blind spot assist, lane keeping assist and plenty of other measures including special attention to pedestrian safety with crumple zones on the body shell, smooth contours, folding mirrors and lots more.

The vehicle undergoes more than 1,000 safety simulation tests and, although crash testing is expensive, it undergoes more than 150 of these procedures too.

Mercedes has been striving for the perfect all-rounder and that includes the title of efficiency champion too.

Enter the 2.2-litre 4-cylinder turbo-diesel with common rail injection model. This delivers 28% lower fuel consumption and CO2 emissions compared to the equally powered six-cylinder engine in the preceding ML300CDI.

So, to put that in people-speak - this model can achieve 1,400km on a single 90-litre tank of fuel - close on 44mpg.

That's equivalent to driving from Stuttgart in Germany all the way to Newcastle. That certainly makes it the efficiency champion in its segment.

But it's not just at the testing centres that the M-Class is put through its paces.

Prototype models are taken to extreme locations such as Namibia and the Arctic to monitor performance and make sure the off-roading capabilities are exceptional too.

Dr Joachim Schmidt, head of sales and marketing at Mercedes-Benz cars said: "We've burned rubber on the racetrack. We've burned our skin in the African desert sun. We've scratched knees and skid plates climbing rocks. And we nearly froze off various body parts in the Arctic. All to make sure that if you don't like to compromise, you'll love the M-Class."

So no expense spared in the preparation and lengths the experts go to producing a new vehicle.Then, the new M-Class made its world debut to a rather loud and lengthy drum roll, which added to the suspense.

And what a looker it is. The curves and build-quality are instantly apparent with Mercedes' attention to fine detail on show at every turn.

The quality of interior design and comfort is certain to leave rival manufacturers scrambling back to the drawing board and that class-leading efficiency will definitely prove difficult to match.

There will be a choice of ultra-modern engines to choose from - all with an emphasis on efficiency and performance. And customers will be able to select their own colour schemes and interior designs with a little help from the experts.

With 1.2 million sales to date since the first generation M-Class was introduced back in 1997, the latest incarnation is a fantastic all-rounder that delivers both on and off road.

Apparently Karl Benz once said: "The love of inventing never dies".

And as Mercedes celebrates its 125th anniversary, the third generation M-Class is testament to that statement.