A British hacker who broke into US military computers looking for evidence of UFOs has lost an extradition appeal. Gary McKinnon, of London, remains free on bail and could appeal to the House of Lords.

McKinnon, who has been charged in US District Court for the Eastern District of Virginia, is accused of deleting data and illegally accessing information on 97 U.S. military and NASA computers between February 2001 and March 2002. He could face up to 60 years in prison.

McKinnon challenged the extradition order in May 2006 but lost. McKinnon's attorney fought against extradition on grounds that his client could be held as an enemy combatant similar to how the US has held other terrorism suspects.

Home Secretary John Reid subsequently approved the extradition order, however, McKinnon took the case to the Court of Appeal.

McKinnon freely admits to hacking but said he never harmed the computers. US officials, however, say his probes caused the shutdown of critical computers used by the military after the 11 September terrorist attacks.

According to McKinnon, his hacking had been timed so that no one was working in the US offices. However, on one occasion he miscalculated the time zones, and someone using a computer that McKinnon had hacked noticed the cursor was moving on its own.

McKinnon used a program called RemotelyAnywhere to control targeted computers. Many of the computers he accessed had their default passwords, which made them easy to access, said McKinnon, who spoke at a security conference in London last year while his appeal was underway.

McKinnon could not be immediately reached for comment.