We've often wondered for what purpose exactly hamsters were put upon this earth, and now we know: to charge mobile phones.

Sixteen-year-old Peter Ash, of Somerset, finally cracked this age-old poser after his long-suffering sister complained of pet hamster Elvis scuttling away for hours during his nocturnal exercise wheel regime.

Ash told Ananova: "I thought the wheel could be made to do something useful so I connected a system of gears and a turbine." He then patched the output to his mobe's charger and voila! - free hamster energy at around thirty minutes' talktime for every two hamster wheel minutes.

Surprisingly - and considering all the current moaning about falling exam standards, etc, etc - Ash only got a "C" for this contribution to his GSCE science course and, undoubtedly, a clean-energy future for all our children. Perhaps if he'd knocked together a desktop cold fusion reactor powered by supercharged, neutron-emitting guinea pigs suspended in deuterium gas he might have earned himself an "A". ®