Critics may have described it as an aerodynamic bathtub but this week sees the 20th anniversary of the launch of the Sinclair C5.

The tiny electric car was designed at the University of Warwick Science Park.

And inventor Sir Clive Sinclair, now aged 64, is unabashed by the commercial failure of his eco-friendly three-wheeler.

He predicts: "Electric vehicles will take over, largely because fossil fuels are declining in availability and because of global warming."

But although they are collectors' items today, only 12,000 of the C5s were ever sold and Sir Clive lost £7 million.

Critics were on his back from the start, describing the battery-powered trikes as aerodynamic bathtubs or oversized electric skateboards.

As bicycle lanes were virtually non-existent, the motoring press also expressed very real concerns about the safety of the invention for drivers - who could be as young as 14.

At the science park a staff of 25, under the leadership of Barrie Wills, developed the C5 which went on to be manufactured at the Hoover factory in Merthyr Tydfil, Wales, and was marketed at £399.

The few still around - in their original box - can sell to collectors for between £1,500 and £2,000.

Last year Sir Clive, who during the 1980s made millions after inventing the world's first pocket calculator and pioneering the market for cheap home computers, launched his latest invention, a foldaway bicycle.

But of the C5 he says: "It suffered negative publicity from the start, largely due to concerns about its safety on the road. It began to get bad press and escalated - then it became fashionable to mock the C5, which was a shame.

"We launched it without preparing people for it and when something is radical and very different, people sort of poke at it and try to find flaws."

The low single-seater vehicle, which had a top speed of 15 miles per hour, was a cross between a car and a bike and had a lightweight polypropylene shell measuring nearly six foot long. This sat on top of a chassis designed by sports car firm Lotus and power came from a battery which needed recharging every 10 to 12 miles.