Janis Sharp, mother of Gary McKinnon, at her home in Hertfordshire after learning the computer hacker will face no further criminal action

Computer hacker Gary McKinnon wept tears of relief after it was decided he would face no criminal action in Britain.

The decision followed a review of the case after the Government's decision to block his extradition to the United States in October on health grounds.

The Director of Public Prosecutions (DPP), Keir Starmer QC, said a joint panel of the Crown Prosecution Service (CPS) and police had decided there should not be a new criminal investigation.

Mr McKinnon, from Wood Green, north London, would have faced up to 60 years in prison if convicted in the US. The 46-year-old, who suffers from Asperger's syndrome, was permitted to stay in the UK after medical reports showed he was highly likely to try to kill himself if extradited. Both Prime Minister David Cameron, who held talks on the case with US president Barack Obama, and his deputy, Nick Clegg, had condemned plans to send Mr McKinnon to the US.

The decision not to extradite "disappointed" the US authorities, but a statement from the US department of justice following the announcement stressed its "continuing collaboration with the CPS and British law enforcement authorities on a wide range of shared concerns".

Mr Starmer said that, between February 1 2001 and March 19 2002, Mr McKinnon allegedly gained unauthorised access to 97 US government computers. A decision was taken that the appropriate place for Mr McKinnon to be tried was the US, which sought extradition. On October 16, Home Secretary Theresa May decided not to extradite him, and added that it was for the DPP to decide whether Mr McKinnon had a case to answer in a UK court.

Mr Starmer said: "None of the reasons for the original decision in 2002 that the appropriate place for Mr McKinnon to be tried was the United States have altered. So far as the evidence is concerned, the position in 2012 is the same as it was in 2002. Most of the witnesses are in the US, as is nearly all the physical evidence and the bulk of the unused material, some of which is sensitive."

He added: "The potential difficulties in bringing a case in England and Wales now should not be underestimated, not least the passage of time, the logistics of transferring sensitive evidence prepared for a court in the US to London for trial, the participation of US government witnesses in the trial and the need fully to comply with the duties of disclosure imposed on the CPS. The prospects of a conviction against Mr McKinnon which reflects the full extent of his alleged criminality are not high."

And he said: "The joint CPS/police panel recommended to the Assistant Commissioner of the Metropolitan Police that he should not commence a new criminal investigation into Mr McKinnon. The Assistant Commissioner of the Metropolitan Police has accepted that advice."

Mr McKinnon's mother, Janis Sharp, said: "I feel fantastic, it's just wonderful. The next thing I would like to get, impossible though it seems, would be a pardon from President Obama. I think it's possible because I think Obama seems like a good person, and so does his wife." She said the news was "amazing because it's my birthday", adding: "Gary was tearful because of the relief - he was so scared. It's going to be such a nice Christmas not to have everything hanging over us."

PA