Gordon Brown unsuccessfully proposed a deal to allow Gary McKinnon to serve any prison sentence in Britain, leaked documents have revealed.
The former prime minister was rebuffed when he suggested the computer hacker could plead guilty in return for not being extradited to the United States.
Mr Brown's offer was included in one of the United States diplomatic cables obtained by Wikileaks and published in The Guardian.
News of the deal came as Mr McKinnon's mother Janis Sharp gave evidence to members of the Home Affairs Committee who are examining extradition law. Mr McKinnon has been at the centre of an extraordinary legal and political tussle as he faces up to 60 years in prison on the other side of the Atlantic.
A High Court decision on whether his extradition could go ahead was adjourned in May and ministers have announced a review of existing rules.
According to The Guardian, Mr Brown made his unsuccessful direct intervention in August 2009.
The move was contained in a secret cable from Louis Susman, Washington's ambassador in Britain, to US Secretary of State Hillary Clinton.
Mr Susman wrote: "PM Brown, in a one-on-one meeting with the ambassador, proposed a deal: that McKinnon plead guilty, make a statement of contrition, but serve any sentence of incarceration in the UK. Brown cited deep public concern that McKinnon, with his medical condition, would commit suicide or suffer injury if imprisoned in a US facility."
The 43-year-old, who suffers from Asperger's syndrome, has admitted hacking into top secret military computers but he said he was looking for evidence of UFOs. Both David Cameron and Nick Clegg have publicly condemned plans to send Mr McKinnon to the United States.
Mrs Sharp said she was "very surprised and very pleased" to learn of the negotiations behind closed doors, adding: "I wish we had known about that because he would have been given credit for it."
