Price: £99,895
Engine capacity: 1.5-litre petrol engine, plus electric motor
Power output (bhp @ rpm): 357 @ 5,800
Top speed (mph): 155
Fuel economy (mpg): 134.5
CO2 emissions (g/km): 49

It's not very often that you get a glimpse into the future. And while I can't be totally certain that the cars of tomorrow will be as striking as the new BMW i8, or mimic its petrol-electric drivetrain and lightweight aluminium construction, I can be sure that the cars we drive in the next 20 years will take a hefty dose of inspiration from BMW's latest green offering.

Until now, most green cars have looked and driven pretty much the same as normal family hatchbacks, often with only the smallest green badge on their rear to show off their environmental credentials. This BMW i8 is different. It's a £99,845 hybrid supercar that claims to deliver a fuel-sipping 134.5mpg with a licence-endangering top speed of 155mph and a 0-60mph time of just 4.5 seconds.

In short, it offers Porsche 911 performance (with arguably better looks) with the economy and emissions – on paper – of a Toyota Prius. Crucially, BMW has done this in a package that dares to be futuristic in style and appearance, without fear that its Marmite lines will put people off. Of course, it's not perfect. The tiny rear seats are a joke, the eco-displays are terribly confusing and lead to information overload, and the swing doors need so much space to open that you are forced to park at the end of rows to avoid embarrassment in a car park.

But by far the biggest problem that I found was that on several long runs out of town, once the 22-mile battery range had been expended, I was left running solely on the i8's 1.5-litre petrol engine. Admittedly, I still managed to beat the fuel economy of a Porsche – BMW has done wonders with turbo-chargers on the i8's tiny petrol unit – but 35mpg is far from the poster-boy green promise.

These are quibbles, though, ranking alongside complaints that the Ford Model T broke down too often. Of course it did, it was revolutionary. And you'd be hard pressed to say that the BMW i8 was anywhere near as revolutionary – it costs a small fortune, far from affordable to the average worker – but it might just be enough to start getting the man in the street excited about green cars. That would be quite an achievement.