Computer hacker Gary McKinnon would no longer pose a serious suicide risk if extradited to the United States, a medical expert has said.
Professor Declan Murphy's latest assessment that the risk of suicide could be managed is significantly different from his view three years ago that McKinnon would require one-to-one observation to avoid a serious suicide bid.
The development could pave the way for Home Secretary Theresa May to authorise McKinnon's extradition to the US to face trial for hacking into military computers 10 years ago.
In his assessment, which was handed to the Home Office last month and broadcast on Channel 4 News tonight, Prof Murphy wrote: "We judge the risk of suicide to be moderate.
"The risk of actual self-harm could be ameliorated by regular contact with mental health professionals and with supportive counselling and listening services of the type that are available within UK prisons."
He added that McKinnon "did not express significant hopelessness or helplessness" and his "suicide plans are not well formulated", the programme reported.
But the psychologist's latest assessment, ordered by the Home Office, was formed despite him being denied any access to McKinnon since his original assessment for the Briton's legal team three years ago, it added.
In 2009 he wrote: "If McKinnon is deported to the United States of America he will require (in my opinion) continual observation on a one-to-one basis during that time period, and for the rest of his incarceration.
"If this does not happen he is likely to make a serious attempt at suicide."
He warned: "McKinnon stated that he would kill himself... He now has a fixed idea, which is currently unshakeable, that his best outcome is to take his own life if deported."
Prof Murphy told the programme he could not comment on the change in his assessment while the case was still being considered by the Home Secretary.
But McKinnon's mother Janis Sharp told Channel 4 News: "What basis could he possibly have to go against the expert opinions of four of the top people in the country, who say that Gary will absolutely take his own life?
"It's an in absentia report and it contradicts his previous face-to-face report. What did he base this on? It's a mystery to everyone."
McKinnon, from Wood Green, north London, has been fighting the prospect of extradition to the US, where he faces up to 60 years in jail if convicted of hacking charges, since he was first arrested in 2002.
He admits hacking but claims he was looking for evidence of UFOs.
A Home Office spokesman said: "After consulting the chief medical officer, the Home Secretary instructed two independent experts to review the case and their report was sent to Mr McKinnon's representatives on February 24 in line with the directions of the court.
"Mr McKinnon and his legal team have until 6 April to respond and make any further representations.
"The Home Secretary will consider the report alongside all other relevant material and aims to reach a decision as soon as is consistent with dealing fairly and properly with this case."
In January, the High Court expressed concern over how long the case was taking to return to court, with two judges listing it for July in a bid to speed matters up.
They acted after hearing that Mrs May was "considering afresh" whether Asperger's sufferer McKinnon should be extradited.
Arrested in 2002, and then again in 2005, an order for his extradition was made in July 2006 under the controversial 2003 Extradition Act between the UK and the US.
Critics claim it is one-sided and favours the US, but an independent review by former Court of Appeal judge Sir Scott Baker last year found it was both balanced and fair.
Shami Chakrabarti, director of civil rights group Liberty, said: "Three leading experts have described Gary McKinnon as a serious suicide risk.
"It's going to take more than one doctor miraculously changing his mind without even re-examining his patient to persuade anyone that an autistic man is fit for extradition."