A real car

The guiding principle behind the Ampera is that owners should get the same safety, practicality, affordable running costs and enjoyment they've come to expect from petrol or diesel Vauxhalls.

In many ways, the Ampera is even simpler than traditionally fueled vehicles: for example, because it always runs on electricity, it develops its maximum torque (274lb ft) from zero revs, so it needs no gearbox - yet it's said to pull away like a car with a 2.5-litre V6 petrol engine.

The platform it's based on is that which will underpin the next Astra family, including the Zafira, and is already in use on the Chevrolet Cruze saloon and the Orlando MPV.

The Ampera is just under 4.5 metres long and 1.8 metres wide, and relies on a perfectly conventional chassis. There's been a lot of detailed work on its aerodynamics, though, to ensure it doesn't waste any of its precious energy cutting a path through the air.

The 180kg of batteries are arranged in a T-shaped pack beneath the floor. In this position they help weight distribution, require no extensive reshaping of the car and don't impinge on passenger space other than restricting the rear to two individual seats.