Hacker Gary McKinnon has lost his final legal appeal to prevent him being extradited and tried in the US.

US authorities claim he hacked 97 military computers and caused $800,000 (£487,000) of damage. McKinnon admits hacking but denies it was malicious.

Two High Court judges ruled in favour of decisions by the Home Office and Director of Public Prosecutions Keir Starmer to send him to the US and not try him in the UK.

Glasgow-born McKinnon now faces up to 70 years in prison if he is convicted in the US of what US prosecutors have called "the biggest military computer hack of all time".

McKinnon has previously appealed unsuccessfully to the House of Lords and the European Court of Human Rights and many experts says the latest judicial review in the High Court was likely to be his last opportunity to avoid extradition.

His lawyers claimed the authorities have not given sufficient consideration to the fact that McKinnon suffers from Asperger's Syndrome, which they said could have "disastrous consequences", including possibly suicide, if he was extradited.

A high-profile campaign by the Daily Mail had given his case a new lease of life, with many celebrities and politicians including Tory leader David Cameron and Liberal Democrat leader Nick Clegg calling for him to be tried in the UK.

His mother Janis Sharp had told the Daily Mail yesterday: "My biggest fear is that if it goes against Gary there would be a plane waiting for him tomorrow night. If we lose, our solicitor will ask for the statutory 28 days to appeal but if they refuse... that's what terrifies me and Gary."

Following today's ruling, Sharp said the family was "heartbroken".

Home secretary Alan Johnson has the power to step in and prevent the extradition of McKinnon but has so far not intervened.

Last week Labour MP Andrew Mackinlay announced he was leaving Parliament after MPs failed to vote in a Commons debate for a review of the 2003 Extradition Act in the wake of the controversy over McKinnon's case, due to extensive pressure from government whips.