self-declared British UFO enthusiast wanted by the US on allegations of hacking into sensitive military networks Friday lost his legal fight against extradition at the High Court in London, according to dpa. Gary McKinnon, 43, had asked the court to overturn a British government decision to allow his extradition, and the refusal by Britain's prosecuting agency to order a trial in Britain. The US authorities allege that he was responsible for the "biggest military hack of all time" that involved 97 government computers belonging to organizations including the US Navy and the space agency Nasa. Lawyers argued that extraditing McKinnon, who suffers from Asperger's syndrome, would have "disastrous consequences'' for his health, including possible psychosis and suicide. They dismissed allegations that McKinnon's actions had been a threat to US national security as a "a complete fantasy." McKinnon has admitted breaking into the US military computers during 2001 and 2002, a period of heightened security in the wake of the September 11 attacks. He has always said he had no malicious intent but was looking for classified documents on UFOs which he believed the US authorities had suppressed. But the US government alleges his conduct was intentional and calculated to influence and affect it by "intimidation and coercion." It has put the cost of repair at more than 700,000 dollars. McKinnon was not in court Friday to hear the judges' decision. But his mother, Janis Sharp, said she feared he might "never see him again" if he was given a long jail term in the US. "We are heartbroken. If the law says it's fair to destroy someone's life in this way then it's a bad law," she said. A further appeal by McKinnon has not been ruled out.