Road Test: Mercedes-Benz G Class G63 6x6 5dr Tip Auto

Up until now, the best chance you'd have to get to drive this monster 6x6 AMG would be to join the Australian army, which signed a contract with Daimler in 2008 to procure 2,100 of these unstoppable desert chasers. But now Mercedes has decided - rather brilliantly - to make a civilian version, ready to order by millionaires before the end of 2013.

From the original military blueprint, it keeps six driven wheels, an off-road low-range ratio in the transfer case, portal axles, five differential locks and a tyre-inflation control system that allows the pressure in the 37-inch tyres to be adjusted in record time, on the move.

But once you climb into the cabin, there's a much less utilitarian bent. Four heated and ventilated leather armchairs, a leather-finished dash with contrast stitching, carbon-fibre trim and Alcantara slathered on the roof headlining and pillars. Pure AMG opulence. And the weirdness doesn't end there. Once you've got over the sheer size of the 6x6, it's worth noting the gigantic carbon wheelarch extensions and a pickup load area featuring an exclusive bamboo lining. Normal, this thing is not.

Did we mention it was big? At 5.85m long and 2.3m tall, it's positively huge. And fast. With the G63's 540bhp, 5.5-litre bi-turbo V8, the G63 AMG 6x6 can hit 62mph in seven seconds. And it does so with no hesitation, the 561lb ft being split in 30/40/30 (front, mid and rear axles) with the help of the familiar 7spd dual-clutch 'box. It just stomps its power to the road. Or whatever surface you happen to be on.

Ok, so the strangest product AMG has ever engineered was likely never supposed to corner like a sports car, but its relative agility is mind-blowing, especially considering that, at 3.85 tonnes, it's a VW Golf heavier than the already mighty G63 AMG.

More than that, it just will not be stopped. By anything. It has axle articulation that would make a Land Rover wince, manages 460mm of ground clearance and has a diving - sorry, fording - depth of a solid metre, 40cm more than the bodystyle it has been derived from. You can take it as read that absolute traction is never an issue, and even if you do begin to slip, you just drop the tyre pressures - independently for each axle, I might add - via switches mounted on the overhead console.

It's the best big boy's toy ever invented. Not a cheap one, though, at something over €300,000. But be honest, can you think of a better way to get your off-road kicks?