LONDON » A High Court ruling on Friday brought Britain an important step closer to extraditing a 43-year-old British computer hacker to the United States despite claims by the man's lawyers that he is a harmless eccentric with a form of autism, and not a cyberterrorist, as U.S. prosecutors have asserted.

The man, Gary McKinnon, has admitted that he hacked into dozens of American military computers from his apartment in north London in 2001 and 2002, saying he was looking for information on UFOs. The latest court ruling rejected his request for a judicial review of a government decision last year approving a U.S. request for his extradition. The court order also rejected his bid to be tried in Britain.

McKinnon's lawyers have spent seven years in a revolving door of hearings and appeals, all unsuccessful. The new ruling leaves them 28 days to review the court's findings and consider other legal avenues, including a possible bid to Britain's new Supreme Court, which will sit next month for the first time. It will replace the Law Lords, for 150 years Britain's highest appeals court.

But judging from statements made by McKinnon's lawyers and relatives outside the court in London yesterday, their hopes now focus on political intervention.

A group of 40 British lawmakers have written to President Barack Obama, asking him to step in and “;bring this shameful episode to an end”; on humanitarian grounds.

Prospects for relief from the British government seem meager, because the British home secretary, Alan Johnson, responded to the new court ruling with a statement reiterating his backing for the extradition.

McKinnon acknowledges hacking into 97 computers belonging to the U.S. Defense Department, Navy, Army and Air Force, and NASA in the months after the Sept. 11 attacks. His lawyers and family have said that his actions were influenced by the fact that he has Asperger's syndrome, a form of autism.

But lawyers acting in Britain to secure McKinnon's extradition have said his actions were not as benign as he has claimed, including the theft of more than 1,000 passwords from high-security networks, damage amounting to $700,000 and evidence of his political motivation to protest U.S. foreign policy.

McKinnon faces eight counts of computer fraud in New Jersey and Virginia. His lawyers and family say he could face a prison sentence of up to 60 years, though U.S. prosecutors have said that he would be likely to get no more than a 10-year sentence.