Audi has confirmed to Autocar that, currently, it has no plans to sell its all-electric R8 e-tron sports car.

Ten of the latest design of R8 e-tron have been built but they will be used exclusively for internal testing and development only.

It's thought that the the cars won't be offered to customers because battery technology hasn't advanced as fast as Audi expected.

Consequently the cost of the batteries has not fallen as much as the company forecast, making the R8 e-tron unviable for series production.

There are also rumours that Audi is not willing to accept the limited range and long charging times that are a result of current battery technology.

In a recent press release, however, it stated: "Through the R8 e-tron, Audi has acquired extensive expertise that will benefit its electrified production models."

The electric Audi R8 e-tron, which uses a lithium-ion battery and a pair of two electric motors, is capable of 0-62mph in 4.2sec.

It's electronically limited to 124.27mph and, in optimal conditions, capable of covering 133.59 miles.