Gary McKinnon, a Glasgow-born computer hacker, has lost his latest High Court bid to avoid extradition to the Unites States of America.

In a 41-page ruling, the judges said extradition was "a lawful and proportionate response to his offending".

Speaking outside the court after the decision emerged, his mother, Janis Sharp, said: "We are heartbroken. If the law says it's fair to destroy someone's life in this way then it's a bad law."

Lawyers for Mr McKinnon, 43, who suffers from Asperger's Syndrome, had been challenging decisions allowing extradition to go ahead and asked judges to overturn a refusal by the Director of Public Prosecutions to allow a trial in the UK. A trial here would block extradition, and he is prepared to plead guilty if put on trial in the UK.

US authorities say that he was behind the "biggest military hack of all time", accessing 97 government computers belonging to organisations including the US Navy and Nasa.

The US government alleges his conduct was intentional and calculated to influence and affect it by "intimidation and coercion". It says the cost of repair totalled more than $700,000.

================================================

RESOURCES

Gary McKinnon case timeline

Gary McKinnon case background

Video - reaction outside court from Gary's mother Janis Sharp

Video - reaction from Mark Lever, chief executive, National Autistic Society

=================================================

He admitted breaking into the system in 2001-2 during a period of heightened security in the wake of the September 11 2001 attacks, but says he was looking for evidence of UFOs.

He was caught trying to download a photograph which he believed was an alien spacecraft from a Nasa computer. He was traced because he used his own email address.

Mr McKinnon's case against extradition has previously been rejected on other grounds by a district judge, the High Court and then, in July last year, the House of Lords. The European Court of Human Rights in Strasbourg also refused to intervene.

His supporters say that a trial in America would not be fair, and that his medical condition, coupled with the stress of extradition and American prison conditions, could result in psychosis and suicide.

A campaign involving family, politicians and celebrities has fought a lengthy battle against extradition.

Speaking after this morning's judgement, Karen Todner, Mr McKinnon's solicitor, said: "This ruling is hugely disappointing. But we shall not stop here.

"Alan Johnson still has the power to act. We have 28 days to review the judgment and will continue to explore every legal avenue until we achieve a just and proper result.

"The Government promised 'ample protection' of individuals' rights, but we have yet to see this in practice.

"Extradition without effective safeguards is a denial of justice for every UK citizen."

If jailed in the US, he could face up to 70 years in prison.