EVERYTHING about the Bentley Bentayga is big. Very big; from size and price to performance.

Especially performance. Proudly presented by its maker as the fastest SUV in the world, putting your foot down hard in a Bentayga sends mature passengers straight back to childhood with fits of giggles.

Only some very grown up words spoilt the impression of a nine-year-old on his first seaside roller coaster ride. This is an almost absurdly quick car.

The bald figures - 187mph and zero to 60mph in four seconds - do scant justice to a leather lined and fiddleback eucalyptus veneered time machine that brings the horizon fast forwarding towards you like a big screen sci-fi time warp tunnel.

Several hundred miles after the first application of the Bentley's 600 horsepower, this was the sensation that lingered longest. Nothing this big and this heavy - it makes a Range Rover look almost lightweight - should go this fast.

Or with this much poise when a corner arrives and you haul off shedloads of speed. With its air sprung suspension set to sport, the Bentayga feels like a car half its 2.5 tonnes weight (a Ford Focus, for example) and seems to bend the laws of physics.

That's what six-litres and a dozen cylinders can achieve when poked with a sharp stick.

Putting all this suave savagery on to the road is helped by the car's all-wheel drive, the same system that would take it impressively off road if you cared little for the rims of its gorgeously huge alloy wheels.

You can now save more than £26,000 and buy a Bentayga with a diesel engine (a Bentley first) that's still plenty quick and will use less fuel than the petrol model, which showed a decidedly dipso 17.6mpg on test.

But, hey ho, if you've got the money you might as well flaunt it. Those petrol powered cylinders make the most wonderful distant roar when provoked, before the car hits its cruise and becomes as hushed as a midnight convent.

And cruising lets you and your passengers appreciate why a Bentley can be such a special place to pass the miles. If you can afford a Bentayga the process of making your car as special as you fancy must be half the fun.

Which means the £162,700 base price is simply a launch pad for your imagination. It might, for instance, stretch to ditching the three-seat rear bench in favour of two airline style seats that massage, warm and adjust for lean at the push of a finger - and all yours for £8,260.

While being warmed and gently pummelled you might like to watch a movie or follow progress on the sat nav map on the screen ahead of you (£5,365) or experience 1,960 Watts of Naim audio (£6,300) which includes 20 speakers and shakes the front seats for extra effect and could be heard on Mars at full tilt.

Yes indeed, huge prices. The car's big too, longer even than the stretched version of the Range Rover tilting its hat at the same market as the Bentayga, and wide enough to make country lanes an exercise in restraint as high-hedged corners approach.

Big enough also in the wheels department to feel them pattering below on bad surfaces. Smooth roads restore the car's sense of gliding along on a cloud, helped no doubt by the standard fit double glazing and optional (£370) deep pile overmats.