This article is more than 12 years old

This article is more than 12 years old

Gary McKinnon, a computer expert who hacked into dozens of US military computers, lost his appeal to the European court of human rights today and faces extradition to the US in the next fortnight, his solicitor said.

McKinnon has fought a long battle with authorities over his extradition to the US, which has dubbed him the "the world's most dangerous hacker".

McKinnon broke into the Pentagon's system from his north London flat and left a message saying "your security is crap".

Last month, he lost his battle against extradition in a House of Lords ruling.

McKinnon turned to the European court of human rights, complaining about the conditions he would face if convicted in the US and was granted a temporary delay.

The court did not give reasons for refusing McKinnon's request today.

Karen Todner, from Kaim Todner solicitors, said her client was "distraught" about the decision. She appealed to the home secretary, Jacqui Smith, to intervene.

"Mr McKinnon has recently been diagnosed as suffering from Asperger's syndrome. As a result, we will be writing to the home secretary again inviting a prosecution in this country," she said.

"Our client now faces the prospect of prosecution and imprisonment thousands of miles away from his family in a country in which he has never set foot.

"Our client's case highlights a worrying trend where UK citizens are at the mercy of the ever-increasing tendency of overseas prosecutors to extend their jurisdiction to crimes allegedly committed in this country."

Using the codename Solo, the 42-year-old hacked into 53 US army computers and 26 US navy computers, including those at the US naval weapons station Earle in New Jersey, which is responsible for replenishing munitions and supplies for the Atlantic fleet.

The US military said he left 300 computers unusable at a US navy weapons station immediately after 9/11.

He was caught in 2002 as he tried to download a grainy black-and-white photograph he believed was an alien spacecraft from a Nasa computer at the Johnson Space Centre in Houston, Texas.

He was easily traced by the authorities because he used his own email address.

Mark Summers, an official representing the US government, said McKinnon's hacking was "intentional and calculated to influence and affect the US government by intimidation and coercion".

American officials claim he caused $700,000 (£354,000) damage and threatened national security.

If extradited, McKinnon faces up to 70 years in prison and his lawyers have argued he could even be given "enemy combatant" status, the same category applied to terrorist suspects interned at Guantánamo Bay.

McKinnon, an unemployed IT worker from north London, has consistently argued that he was merely a "bumbling computer nerd" who caused no damage but was merely searching for evidence of extraterrestrial life.

"It got a bit silly," he told the Guardian in 2005. "I suppose it means I'm not a secretive, sophisticated, checking-myself-every-step-of-the-way type of hacker."

Between 2001 and 2002 he scanned thousands of US government computers from his bedroom, looking for loopholes which would help him get inside their networks in order to prove his contention that the existence of aliens had been covered up by the CIA.

After last month's House of Lords decision, McKinnon said the case had proved devastating in the six years since he was arrested. With his bail conditions barring him from using the internet, a return to his previous work in IT had been nearly impossible and potential employers were scared off.

"I've lost two jobs because of this; my bosses just didn't want to be associated with the publicity," he said.

Todner denied McKinnon was a terrorist or a terrorist sympathiser and said his case could have been dealt with by our prosecuting authorities in Britain where the hacking raids were conducted. "American officials involved in this case have stated that they want to see him fry. The consequences he faces if extradited are both disproportionate and intolerable and we will be making an immediate application to the European court to prevent his removal."

McKinnon would face a much shorter sentence under Britain's computer crime laws. The defence has argued he is being unfairly targeted because his work embarrassed the US security services, and that an attempt by US prosecutors to make a deal with McKinnon - in which he would be offered a six-month sentence for his cooperation - constituted an unfair derailment of British legal procedures. That contention was rejected by the law lords, who said granting the appeal would "imperil the integrity of the extradition process".

Lord Brown of Eaton-under-Heywood said in the written judgment: "The difference between the American system and our own is not perhaps so stark as the appellant's argument suggests."

Computer security experts said it was unlikely US prosecutors would give up their pursuit. "The US is making a clear stand that anyone making any attempts to compromise its computers and data will face the consequences," said Graham Cluley of the IT security company Sophos.

McKinnon's extradition was brought under the controversial Extradition Act 2003, which was designed to deal with terrorist suspects but has been applied in cases where terrorism has not been the primary concern.

Under the act, America authorities are able to demand a Briton's extradition without having to provide evidence. However, Britain has to prove its case in a US court to extradite US citizens to the UK.

The so-called Natwest Three were extradited under the same legislation in 2006 and this year sentenced to 37 months' imprisonment.

Among the act's critics is the former Tory MP Boris Johnson, now the London mayor, who in 2005 called for extradition of British citizens to the US to be suspended.