Tesla Motors, California-based maker of the electric Elise -- aka Tesla Roadster -- is to make a four-seat saloon, rivalling the BMW 5-Series -- and there'll be an update of the Roadster by the end of the decade.

Company vice-president Mike Harrigan told Autocar that the electric motor goes upfront along with the batteries, and that it'll be rear-wheel drive. Unlike the Tesla, it'll be sold globally, including the UK.

However, it seems unlikely that Lotus will supply the underpinnings of the new car, as it did for the bonded aluminium-based Tesla Roadster. Instead, the machine seems likely to be made of lightweight steel, with some 10,000 to 20,000 units turned out annually.

The company reckoned that new battery technology means it will be able to sell two versions of the car in the UK. The £30,000 entry-level car will offer similar output to the 185kW Roadster with a 200 mile range, while the £40,000 luxury variant gets more powerful batteries and a 300 mile range between charging stops.

There'll also be a top-end £55,000 version of the Roadster at some point, probably by 2010. (pistonheads)