British computer hacker Gary McKinnon will not face charges here in the UK, the director of public prosecutions has confirmed.
McKinnon, who is still wanted for trial in the US, had his extradition halted by home secretary Theresa May three months ago.
McKinnon has been fighting extradition to the US since 2002. He was accused of hacking into US government computers, but has always denied any malicious intent and claimed he was looking for information relating to UFO activity.
McKinnon was described as the "biggest military hacker of all time" and caused $800,00 worth of damage, it is alleged. If found guilty in the US McKinnon could face up to 60 years in prison.
McKinnon, 46, suffers from Asperger's syndrome and it was ruled by May that extradition to the US could result in him attempting to take his own life.
A joint statement by Keir Starmer QC, Director of Public Prosecutions (DPP), and Mark Rowley QPM, Assistant Commissioner of the Metropolitan Police Service, said that after the decision was taken not to extradite McKinnon to the US, the DPP had to decide whether a criminal investigation should take place in the UK.
They decided that as nearly all the evidence and the majority of the witnesses are US based, bringing a case in the UK would have proven to be logistically difficult.
"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 to fully comply with the duties of disclosure imposed on the CPS," the statement said.
"The prospects of a conviction against Mr McKinnon, which reflects the full extent of his alleged criminality, are not high," it added.
"After consulting with the Metropolitan Police Service and the CPS and having carefully considered matters, on 4 December this year, US authorities indicated to us that they would be willing to co-operate with a prosecution in England and Wales if that would serve the interests of justice," the statement explained.
The statement went on: "However, they do not consider that making all the US witnesses available for trial in London and transferring all of the US material to this jurisdiction would be in the interests of justice given our representations and the reasons for the decision that the US was the appropriate forum as set out above. That is a decision the US authorities are fully entitled to reach and we respect their decision."