YOU don't jump aboard BMW's extraordinary i8, instead you enter carefully with bottom to the fore and then pull your legs in afterwards. Not very elegant but absolutely worth the effort.

For the big doors that hinge themselves upward are a less than subtle hint that with the i8 BMW broke the mould to show the world (or the wealthier parts of it) how the future might look.

And standing a few metres from the i8, that future looks pretty darned exciting.

For here is a car that not only grabs attention like nothing else on four wheels but is a rolling demonstration of what clever engineers and a generous budget can provide.

Firstly, it's built of aluminium and carbon fibre - that expensive stuff that makes Lewis Hamilton's Sunday afternoon car so tough. It must be one reason why the i8 doesn't come cheap - with a £104,540 list price before you pile on any options.

Another reason for the size of the bill is the way the car is powered; with a special version of the same three-cylinder petrol engine you can find in a Mini Cooper at the back, and a beefy electric motor at the front.

Between them, and running down the centre of the cockpit are the batteries that give the i8 up to 23 miles of near silent motion when they're fully charged.

That's all very eco-friendly, and responsible for the i8's highly favourable business user BIK rating (9 per cent) and wildly inaccessible official fuel consumption of more than 134mpg. Blame the lawmakers for that latter nonsense.

In the real world your consumption depends how far you go before recharging the batteries, but you'll still do better than people spending the same large dollop of cash on a conventionally petrol-powered head turner, like a Porsche 911 or Audi R8.

And you won't be lusting after an i8 because it might save you money. Of course not; you want one because it looks so absurdly cool. It does, but not in a contrived way. This is a serious car and it wants you to know it.

Not so serious that you won't be grinning for most of the drive. Once your right foot goes down with some intent both petrol and electricity combine to produce the sort of push you get when a fighter pilot releases the brake at the end of the runway.

This rush to the horizon is accompanied by a glorious howl from the petrol engine some feet behind you and will continue on a test track (or autobahn when the traffic clears) to a heady 155mph, where BMW reins the car in and cries 'enough'.

So it looks amazing and goes very fast indeed. What about the practical side of i8 ownership?

Well, it is exquisitely put together for starters, with a cabin that's both surprisingly conventional (no hidden shocks for BMW veterans) and equipped with a couple of little seats in the back for wide-eyed kiddies.

It also rides pretty well on its big wheels, although you wouldn't call the car quiet. It's possible to upgrade the standard sound system but you might not want to bother.

With a full tank of petrol and a charged battery the i8 also has a thoroughly practical range (BMW suggest better than 300 miles) and won't leave you stranded when the battery is flat - simply head for a filling station's petrol pump.