Gary McKinnon, the British hacker facing extradition to the US for breaking into American military computer systems, has lost a final legal challenge in the High Court.
Mr McKinnon admits hacking into military and Nasa computers but says he was on a "moral crusade" to find classified documents about Unidentified Flying Objects (UFOs), not a malicious individual bent on bringing down US military systems.
This is not a view shared by the American authorities, who say his actions in 2001 and 2002 caused $800,000 (£487,000) damage - something he disputes.
They also accuse him of immobilising sensitive systems in the months following the 9/11 attacks.
If extradited and convicted in the US, the Glasgow-born computer enthusiast, who now lives in Wood Green, north London, could face up to 70 years in prison.
His case has attracted widespread publicity and a range of celebrities as diverse as Terry Waite, Sting and Julie Christie, as well as politicians from all the major parties, have called for him to be freed or at least tried in the UK.
It has focused debate on what some see as the imbalance in the extradition treaty between the US and UK, under which, critics say, it is much harder for a UK application to be successful.
The Daily Mail reported that the prime minister said he was sympathetic to the case of Mr McKinnon, who was diagnosed with Asperger's syndrome - a form of autism - last year, and it raised a number of issues.
American authorities allege between February 2001 and March 2002, Mr McKinnon, 43, hacked into dozens of US army, navy, air force, and Department of Defense computers, as well as 16 Nasa computers.
They also say Mr McKinnon altered and deleted files at a US naval air station not long after the terrorist attacks on 11 September 2001.
They describe Mr McKinnon's hacking as "intentional and calculated to influence and affect the US government by intimidation and coercion".
But Mr McKinnon, or Solo as he was known online, has always said he is no web vandal, or virus writer, and he never acted with malicious intent.
In a BBC interview in 2005 he said: "I found out that the US military use Windows and having realised this, I assumed it would probably be an easy hack if they hadn't secured it properly."
Using commercially available software, Mr McKinnon probed dozens of US military and government networks. He found many machines without adequate password or firewall protection. So, he simply hacked into them, he said.
Earlier this week, he told the BBC in another interview: "I am not blind to criminality, but I was on a moral crusade.
"I was convinced, and there was good evidence to show, that certain secretive parts of the American government intelligence agencies did have access to crashed extra-terrestrial technology which could, in these days, save us in the form of a free, clean, pollution-free energy."
He added: "I thought if someone is holding onto that, that is unconstitutional under American law. I didn't think about jail sentences at the time."
Mr McKinnon got his first computer when he was 14-years-old. He left school at 17, and became a hairdresser. But in the early 1990s some friends convinced him to get a qualification in computers.
After completing a course he started doing contract work in the computing field.
By the late 1990s Mr McKinnon decided to use his hacking skills to "research" his belief the US government was withholding critical information about UFOs.
His search quickly turned into an obsession.
"I'd stopped washing at one point. I wasn't looking after myself. I wasn't eating properly. I was sitting around the house in my dressing gown, doing this all night," he said.
Mr McKinnon did not try very hard to cover his tracks, even using his own e-mail address. When Britain's hi-tech crime unit finally came for him in 2002, Mr McKinnon was not surprised.
He told the BBC: "I think I almost wanted to be caught, because it was ruining me. I had this classic thing of wanting to be caught so there would be an end to it."
He thought he would be tried in Britain, and that he might get, at the most, three to four years in prison.
Then, later that year, the US decided to indict him although extradition proceedings did not begin until 2005.
He has since appealed unsuccessfully to the House of Lords and the European Court of Human Rights to avoid extradition.
One of his major arguments against extradition is that he believes he will not get a fair trial in the US and will be punished much more severely because he has contested the extradition process.
In February his lawyers lost an appeal for him to be prosecuted in the UK on lesser charges. The Crown Prosecution Service said the US was the best place for the case to be heard.
Now his legal team is arguing his Asperger's syndrome should have been considered by the home secretary when she gave the go-ahead for his extradition in October.
Mr McKinnon was diagnosed with the condition only last August after an expert in autism watched him in a television interview and contacted his solicitor.
The initial hunch was confirmed by Professor Simon Baron-Cohen, a leader in the field.
Asperger's syndrome sufferers commonly become obsessed with certain activities and interests and have a level of social naivety when it comes to evaluating the consequences of their actions.
Prof Baron-Cohen said this was consistent with Mr McKinnon's "obsessive search for truth".
He said of Mr McKinnon's actions: "We should be thinking about this as the activity of somebody with a disability rather than a criminal activity."
He added: "Someone with Asperger's syndrome will find it very difficult to tolerate a prison environment."