By Tim Castle
LONDON (Reuters) - A British computer hacker accused by the United States of causing more than $700,000 damage to U.S. military systems will not be extradited because of the high risk he could kill himself, Britain's Home Secretary Theresa May said on Tuesday.
Gary McKinnon, who has been fighting extradition for seven years, faced up to 60 years in a U.S. jail if found guilty of what one U.S. prosecutor called the "biggest military computer hack of all time".
McKinnon, 46, admits hacking into Pentagon and NASA computers under the pseudonym "Solo" but said he was looking for evidence of UFOs.
The former computer systems administrator has Asperger's Syndrome, a form of autism, and is suffering from depressive illness. He has been fighting extradition since British police arrested him in 2005.
"I have concluded that Mr. McKinnon's extradition would give rise to such a high risk of him ending his life that a decision to extradite would be incompatible with Mr. McKinnon's human rights," May told parliament.
"I have therefore withdrawn the extradition order against Mr. McKinnon."
His case was one of the most high-profile extradition decisions ever faced by the British government.
Campaigners had said it highlighted the unbalanced nature of Britain's extradition treaty with the United States, arguing it was easier to send a British suspect to the United States than the other way round.
Prime Minister David Cameron expressed sympathy for McKinnon before coming to power in 2011 and raised concerns over the extradition agreement with U.S. President Barack Obama earlier this year.
British legislators had demanded an overhaul of the treaty, signed in 2003 to speed up transfer of suspects between the two allies, saying it was biased in favor of the United States and failed to protect the rights of British citizens.
May said she would introduce legislation to allow British judges to block the transfer of suspects to a foreign court in extradition cases.
"I have decided to introduce a forum bar. This will mean that where prosecution is possible in both the UK and in another state, the British courts will be able to bar prosecution overseas, if they believe it is in the interests of justice to do so," May said.
U.S. officials say McKinnon accessed 97 military and NASA computers in 2001 and 2002, disabling naval systems and causing more than $700,000 of damage.
May said she had taken her decision not to extradite him after studying medical reports and taking extensive legal advice.
"Mr. McKinnon is accused of serious crimes, but there is also no doubt that he is seriously ill," she said.
It would now be up to British prosecutors to decide whether McKinnon had any case to answer in a British court, May said.
There was no immediate reaction from the U.S. government or its London embassy. The decision was praised by campaigners, legislators and McKinnon's family.
"Thank you Theresa May from the bottom of my heart. I always knew you had the strength and courage to do the right thing," the BBC reported his mother Janis Sharp as saying.
(Editing by Janet Lawrence)