Never mind the mockers, Del Boy's little plastic runaround is about to make an electrifying comeback ...

A pollution-free, electric version of the three-wheeled Reliant Robin car is under development. An advanced prototype is due to be completed this autumn, and the battery-powered production version could be on sale by the end of next year.

The little runabout is best known for mobilising Del Boy and Rodney in the BBC series Only Fools and Horses. But its real life manufacturer in Tamworth, Staffordshire, has horizons even wider than Trotters' Independent Trading. Reliant hope to sell some of the electric Robins in smoggy southern California, where there are Government incentives to promote sales of non-polluting cars.

The company is aiming for a car with a top speed of 65 mph and a range of 70 miles before an overnight battery recharge is needed. "It has got to be able to keep up with the other traffic and go a reasonable distance," said Reliant's managing director and part-owner, Jonathan Heynes, a former executive with Jaguar Cars.

But acceleration would be faster than the existing petrol- engined Robin, whose 850cc aluminium engine gives it a top speed of 80 mph.

The reason why the fibreglass-bodied Robin is well suited for conversion to electric drive is its weight - just two-thirds that of a four-wheel, steel-bodied car of similar size.

That lightness sharply reduces the amount of power it consumes in accelerating. And that, in turn, allows the Robin to attack the biggest bugbear of electric vehicles: in order to have a tolerable range between recharges they need to carry a large weight and volume of batteries.

The three-wheeler should need less battery bulk.

The vehicle uses one lightweight, high-efficiency and British-built Lynch electric motor. The plan is to sell the car at a premium price above the pounds 7,000 which the petrol version costs.

"By October or November we hope to have completed a good, realistic prototype, a `test mule', which we can critique," said Mr Heynes, who purchased the struggling company along with two partners last year.

He will not show the vehicle off or discuss its engineering, for fear of exciting premature interest. Even so, the company gets about two letters a week from among the 44,000 Reliant owners inquiring about the prospects for the electric car.

Reliant, founded in 1935, now employs 110 people and produces 25 petrol Robins a week after being moribund for months. In its heyday in the 1970s 2,500 staff made nearly 300 vehicles a week including the now-defunct Scimitar sports car.

During the 1990s the company was twice in receivership and once in administration. Then Mr Heynes, aged 51, purchased Reliant in partnership with an anonymous backer and the Mancunian entrepreneur Kevin Leech, who owns Land's End and John O'Groats. Mr Heynes said: "It has always been the parent companies which have run into problems, never Reliant itself. It's a very good trading name, and we're convinced we can turn it round."

The Robin can be driven by people with only a motorbike licence and the tax disc is half the price of a conventional car. For the electric version, that disc will be even cheaper.