A man who claims to have developed a free energy technology which could power everything from mobile phones to cars has received more than 400 applications from scientists to test it.

Sean McCarthy says that no one was more sceptical than he when Steorn, his small hi-tech firm in Dublin, hit upon a way of generating clean, free and constant energy from the interaction of magnetic fields. 'It wasn't so much a Eureka moment as a get-back-in-there-and-check-your-instruments moment, although in far more colourful language,' said McCarthy. But when he attempted to share his findings, he says, scientists either put the phone down on him or refused to endorse him publicly in case they damaged their academic reputations. So last week he took out a full-page advert in the Economist magazine, challenging the scientific community to examine his technology.

McCarthy claims it provides five times the amount of energy a mobile phone battery generates for the same size, and does not have to be recharged. Within 36 hours of his advert appearing he had been contacted by 420 scientists in Europe, America and Australia, and a further 4,606 people had registered to receive the results.