A prototype vehicle has been built by Mercedes-Benz scientists who say it produces no harmful exhaust emissions at all. The equipment has been installed in a six-seater V-class people carrier which now has a top speed of 62 mph and a range of 155 miles. It is also whisper quiet.

The research team unveiled the electric NECAR II (it stands for New Electric Car) following five years development. Two years ago the fuel cell components were so bulky that they could be fitted only in a Mercedes-Benz van taking up the entire cargo space. Now the fuel cells fit under a flap in the floor and there is almost as much room inside as in a conventionally powered vehicle.