Lawyers for the Home Secretary have agreed to delay moves to extradite Gary McKinnon, the computer hacker, pending a review of fresh psychiatric evidence.

Last week Mr McKinnon, who has Asperger’s syndrome, was refused permission to take his case to the Supreme Court and faced 14 days to make representations. But government lawyers have now said that they will set aside the 14-day deadline to take time for consideration of the evidence.

Karen Todner, Mr McKinnon’s lawyer, said: “We do take some hope from this. It is the first time that Alan Johnson will have a proper opportunity to consider the reports in this case and it shows that he is taking it seriously. In the meantime we don’t want to be hammering on his door.”

Mr McKinnon, 43, from North London, is wanted by US prosecutors for what they have called the “biggest military computer hack of all time”. He faces up to 70 years in prison if convicted.

Two High Court judges last week refused him leave to appeal to the United Kingdom’s highest court.

Lord Justice Stanley Burnton said: “His extradition is a lawful and proportionate response to his alleged offending.”

The US authorities claim that he hacked into 97 military computers and caused £487,000 in damage. Mr McKinnon admits hacking into Pentagon computers but denies that it was malicious. He argues that the case should be tried in Britain.

His lawyers claim that the authorities have not given sufficient consideration that Mr McKinnon’s Asperger’s syndrome could have “disastrous consequences” if he was extradited.

Janis Sharp, his mother, said last week that he was suicidal. His actions had been born of “compulsive and obsessive behaviour” and did not justify extradition, she added.

The US Government alleges that between February 2001 and March 2002 the computer enthusiast hacked into dozens of US Army, Navy, Air Force and Department of Defence computers and 16 at Nasa.

They claim that he altered and deleted files at a US Naval Air Station soon after the September 11 terrorist attacks and rendered critical systems inoperable.

At one point, he took down an entire network of US army computers with the aim, they allege, of accessing classified information.

Mr McKinnon describes himself as a “bumbling computer nerd.” He says his aim was to find evidence of a UFO cover-up and expose it.

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