"Mobile phone operator Orange said on Tuesday it had teamed up with GotWind, a firm specializing in renewable energy, to produce a recharger powered by dance energy alone.

The portable kinetic energy chargers will be given a test run at this year's Glastonbury Festival.

Orange said the prototype chargers weigh the same as a phone and are about the size of a pack of cards.

Attached to the user's arm, they employ a system of weights and magnets which provide an electric current to top up charge in a storage battery. This can then later be used to recharge the phone.