full article By Jonathan Fildes Technology reporter, BBC News, Oxford

A system that can deliver power to devices without the need for wires has been shown off at a hi-tech conference.

The technique exploits simple physics and can be used to charge a range of electronic devices.

Eric Giler, chief executive of US firm Witricity, showed mobile phones and televisions charging wirelessly at the TED Global conference in Oxford.

He said the system could replace the miles of expensive power cables and billions of disposable batteries.

"There is something like 40 billion disposable batteries built every year for power that, generally speaking, is used within a few inches or feet of where there is very inexpensive power," he said.

Trillions of dollars, he said, had also been invested building an infrastructure of wires "to get power from where it is created to where it is used."

Witricity claims to be able to charge gadgets large and small

"We love this stuff [electricity] so much," he said.

Mr Giler showed off a Google G1 phone and an Apple iPhone that could be charged using the system.

Witricity, he said, had managed to pack all the necessary components into the body of the G1 phone, but Apple had made that process slightly harder.