Janis Sharp told a fringe meeting of the Conservative Party conference that its pledge to rewrite the country’s “one-sided” extradition agreements would come too late to save Glasgow-born Gary McKinnon from being sent to the US for trial.

Mr McKinnon, 43, who suffers from Asperger’s Syndrome, is accused by the authorities of infiltrating Pentagon and Nasa computer networks in what has been described as the “biggest military computer hack of all time”. He faces a possible 60 year maximum jail sentence.

“I’m not confident the High Court will allow him to go to the Supreme Court, if not he will apply to the European Court, “ said Mrs Sharp. “But with the Nat West three the European Court considered their case while they were sent to the US. We’re the only country in the world doing this to its own people.”

Mrs Sharp spoke after Dominic Grieve, the Shadow Justice Minister, promised an incoming Conservative government would rewrite the “one-sided” laws to make sure that evidence for extradition cases would be heard in the UK.

Mr McKinnon will learn by the end of this week whether he can appeal to the new UK Supreme Court against extradition under a 2003 act, brought in after the September 11 terrorist attacks.

Under the law the US government does not have to provide a prima facie case when requesting that a suspect be extradited, causing dissatisfaction among civil liberties campaigners.

“The Americans want to give Gary 10 years on every count because he has embarrassed them,” Mrs Sharp told a meeting hosted by the National Autistic Society, which is supporting his case.

His medical condition, diagnosed after the publicity surrounding his arrest, was entered as a factor in his latest appeal but that was rejected by the High Court. Medical experts have concluded there is a grave risk to his health if he is extradited to the US.

Mr McKinnon’s legal team claim the new supreme court of England and Wales must hear the appeal under the European convention on human rights. They argue that because the court has agreed to hear an appeal against extradition to the US brought by Ian Norris, a businessman who has prostate cancer, that ruling should also apply to their client.

“This is seven-and-a-half years and it is inhumane and it is wrong,” said Mrs Sharp. “Gary has been in a really bad way, nearly suicidal. This is on our minds 24 hours a day.”

Mr McKinnon, 43, who lives in north London, was arrested in 2002 after American prosecutors accused him of hacking into computer systems of the US Army, Navy, Air Force, Department of Defence and Nasa, as well as sabotaging vital American military systems.

The US authorities say his actions caused hundreds of thousands of pounds worth of damage. Mr McKinnon says he was searching for information on UFOs held by the US government, and his supporters have said it was just an obsession that went too far.

Although he failed to keep any evidence of extraterrestrial technology he left anti-war messages on US government computers. He was traced by the authorities because he used his own e-mail address.

Throughout his time hacking, Mr McKinnon said that he was no expert, categorising himself as a nerd who had simply exploited loopholes in commonly-used software, claiming that sensitive networks were left unsecured or with the default password still in place.

More than 70 MPs have signed a motion calling for his extradition to be halted but the Home Office has started that it is illegal for the Home Secretary to intervene.