"US foreign policy is akin to government-sponsored terrorism these days . . . It was not a mistake that there was a huge security stand-down on September 11 last year . . . I am SOLO. I will continue to disrupt at the highest levels . . ."

These words, left on one of 97 computers hacked at NASA and the Pentagon between February 2001 and March 2002, were not the chilling threat of a terrorist or the start of an episode of 24 but a personal message to the US Government from unemployed Glasgow-born computer systems administrator, Gary McKinnon. They were sent not from his underground island lair but from the bedroom of his girlfriend's aunt's house in London. They marked not the beginning of a concerted attack on the US defence infrastructure but part of Gary's continued quest for proof of the existence of UFOs.

As a result of his ready detection (he used his own e-mail address) Gary has been on the couch with Richard and Judy and there is even a song, "Change the World", about his case, but, according to the US authorities, he is guilty of "the biggest military hack of all time" and they want him sent to the States to face charges which could see him jailed for up to 70 years. Extradition proceedings were started in June 2005, although the delay seems odd as Gary was first arrested and interviewed by English police in March 2002. In 2003 he was offered a plea bargain with a likely sentence of about three years imprisonment and a return home after only six months in a US jail. The other side of that offer was eight to 10 years in prison, and no return home for any of it, if he did not plead guilty. Gary declined.

Gary has admitted what he did, although he denies causing over $700,000 worth of damage alleged by the US to have been done by his hacking. He has made an open offer to plead guilty in England under the Computer Misuse Act, even admitting guilt in a formal witness statement. Despite this the Director of Public Prosecutions (DPP) refuses to prosecute, claiming that he is unable to do so. He is wrong. Similar prosecutions have been brought.

Fellow Asperger's sufferer Aaron Caffrey was tried (and acquitted) at Southwark Crown Court of the 2001 systems crash involving the navigational network at Houston, Texas.

A 19-year-old Richard Pryce ("the Datastream Cowboy") was fined £1200 for the "schoolboy prank" of using his hacking of a US Air Force computer system to infiltrate the system of a South Korean atomic research institute during sensitive negotiations between the US and North Korea.

Gary McKinnon was in London when he hacked into the systems. If prosecuted anywhere it should be in England. The DPP appears more unwilling to act than unable to do so.

It is hard not to be aware of the firm grip on the shoulder from our special friend across the Atlantic, and his willingness to use extradition arrangements which seem to emasculate our courts' ability to test the evidence and protect British citizens.

If there is any positive, or perhaps mixed, aspect of Gary's case, it may be that he now knows that he suffers from Asperger's Syndrome, a form of autism. When interviewed on TV in relation to an unsuccessful appeal to the House of Lords, Gary was seen by various experts who suspected that he may suffer from the syndrome. The suspicion was subsequently confirmed by formal diagnosis in August 2008. It is said to help explain his hacking activities. Unfortunately the Home Secretary considers it irrelevant to the question of extradition, despite a tradition in the US of poor treatment of those with mental health issues.

Gary's Asperger's is likely to make his stay in a US prison unbearable, to the extent even that it is feared that he may commit suicide. Together with the ability to prosecute him in England his Asperger's should seal the refusal to extradite him. The signs are not good because the law is not good, especially where it touches on anti-terrorism.

Function creep is a symptom of New Labour. We have seen it with Regulation of Investigatory Powers legislation, inappropriately used by local authorities to investigate fly-tipping, dog-fouling and policing school catchment areas.

We saw it also with the use of anti-terror laws to freeze assets in an Icelandic bank at the start of the collapse of world banking, and with the use of such powers to stifle Walter Wolfgang's mild dissent at the Labour Party conference in 2005.

Although extradition was never said to relate exclusively to terrorist offences, the current arrangements were sold to us mainly as a weapon in the war on terror.

Last week the Commons debated the US/UK Extradition Treaty and the Extradition Act 2003. The Government outvoted those who wanted a review of the workings of extradition. They did so with the votes of some who had spoken in favour of Gary McKinnon.

There was a stench of hypocrisy in the air, made more acrid by the shameful contribution of Denis MacShane, who compared Gary's condition to Ernest Saunders' conveniently disappearing pre-senile dementia. Westminster appears prepared to allow the current situation to continue without even a review, notwithstanding the many critics.

Even the Government's own independent reviewer of our anti-terror laws has said that Gary should be prosecuted here and certainly not sent to the US. In The Herald in February Joseph Gutheinz, a retired senior special agent for NASA's Office of Inspector General, and now a college lecturer in criminal justice, urged an end to Gary's extradition proceedings and questioned the ability of the US justice system to deal appropriately with someone who suffered from Asperger's.

Gary's case has been through the High Court, House of Lords and European Court of Human Rights. It is once more before the High Court with the review of the refusal by the DPP to prosecute, and the implications of Gary's Asperger's. Some news is expected this week. The courts in England have few remaining opportunities to do the right thing if the DPP refuses to do so. If the law proves this week to be the obstacle to doing the right thing then it is simple - the law must be changed.

John Scott, Solicitor Advocate, is chairman of the Howard League for Penal Reform in Scotland.