Audi R8 e-tron (road car)

I've been driving Audi's all-electric supercar. It was huge fun. Well, it's been a long time coming. And after all that, it's not long going.

If you've a long memory you might remember a concept from 2009 simply called the Audi e-tron. It looked slightly like an R8 but it wasn't. The body was very different - it was even a different size - and it had pure-electric drive. Each of the four wheels had their own motor. Audi said it would go on sale in 2013.

Rash thing to say. During development the concept got watered down, so finally it's RWD only (though more powerful than originally planned), and uses a body the same size and shape as the R8's - although a quarter of it is carbonfibre to cut the weight. And then they decided it wouldn't, after all, go on sale.

They've built ten fully-developed prototypes, they're road-legal, and they will be used in trials to gather data on battery performance and electronics. These parts are modular across the whole VW group, so it's good info. Even so, it's not the original pledge.

Overall weight is 1780kg. The chassis is absolutely chocka with exotic components to cut weight versus the standard R8. The heavy engine and gearbox are absent of course, too. But that doesn't offset the mass of the huge battery. At least it sits low and centrally in the car, so it isn't bad for cornering.

There are two motors in the middle of the rear, and each drives one wheel. They aren't mechanically linked, so there's no diff. Each motor makes 140kW (190bhp) so that's 380bhp in all. At low speed there's all the acceleration the tyres can use, and 0-62mph disappears in 4.2 seconds, but the acceleration would peter out towards the motors' rev limit at about 150mph, so instead the car is limited to 125mph for efficiency's sake.

It works amazingly well, and yet the car feels natural, easy to predict and understand. Switch the ESP to 'sport' and it'll even drift a bit. It's astonishing how quickly the e-motors can react to changing circumstances: far faster and more subtly than using brakes or cutting and reinstating the power in normal ESP systems.

But Audi boss Wolfgang Duerheimer gives other reasons. "We are a premium company. Our customers don't want to miss out on any day-to-day desire." The desire he refers to is that of arriving at your destination. He means that being stuck by the roadside with a flat battery isn't a premium experience.

He also says the R8 e-tron would be too expensive to build - all that carbon, all that battery. This means it would have to sell at a loss. "If we used the A3 and A4 to subsidise a flagship, well that's not very polite to those customers," he says icily.