The British national Gary McKinnon today lost his high court bid to avoid extradition to the US for allegedly carrying out the "biggest military computer hack of all time".
The case dates back to 2001, when it is alleged Mr McKinnon hacked into computers belonging to the US military and scientific establishments from his home in Wood Green, north London.
Under the codename Solo, he is said during a period of 18 months to have hacked into hundreds of machines belonging to the Pentagon, the US army and air force and Nasa not properly secured by officials.
US prosecutors say he caused $700,000 (£375,000) worth of damage. A lawyer for the US government said the hacking "was intentional and calculated to influence and affect the US government by intimidation and coercion".
In an interview with the Guardian in 2006, Mr McKinnon claimed he had simply been searching for evidence of UFO activity.
The charges include one incident - shortly after the terrorist attacks on September 11 2001 - that brought down a network of 300 computers at the Earle naval weapons station in New Jersey. Another raid allegedly knocked out 2,000 computers in Washington.
Mr McKinnon had challenged a decision by the home secretary, John Reid, to send him to the US.
Mr Reid decided last year that Mr McKinnon's extradition should go ahead despite claims from his lawyers that the 40-year-old faced the prospect of a military tribunal and potential internment in Guantánamo Bay as a so-called enemy of the state. He faces a sentence of 70 years if found guilty.
"We do not find any grounds of appeal against the decision," said one of the judges, Lord Justice Maurice Kay.
"Mr McKinnon's conduct was intentional and calculated to influence and affect the US government by intimidation and coercion."
He added: "As a result of his conduct, damage was caused to computers by impairing their integrity, availability and operation of programmes, systems, information and data ... rendering them unreliable,"
Mr McKinnon's lawyers had argued that sending him to the US would breach his human rights and should not be allowed on the basis that his extradition was sought "for the purpose of prosecuting him on account of his nationality or political opinions."
Edmund Lawson QC, appearing for Mr McKinnon, described to the court how solicitors had been told of the "determination of the New Jersey authorities to see Mr McKinnon fry" during plea bargaining negotiations in 2003.
Mr McKinnon was warned by US prosecutors he could receive a longer sentence and be denied repatriation to serve his sentence in the UK if he did not go to the US voluntarily.
The judges said: "Viewed from the perspective of an English court, the notion that a prosecutor may seek to induce a plea of guilty on the basis that substantial benefits would be withdrawn if one is not forthcoming is anathema."
The extradition proceedings have taken so long because the UK sought assurances that Mr McKinnon would not face a military tribunal and would not serve his sentence at Guantánamo Bay.
The legal process could continue, as Mr McKinnon plans to apply to the House of Lords, Britain's highest court, for permission to challenge today's high court ruling. His lawyers are expected to focus on "coercive" legal US tactics aimed at persuading Mr McKinnon to plead guilty.