The mother of British computer hacker Gary McKinnon has welcomed Home Secretary Theresa May's decision to block his extradition to the US.
Janis Sharp said she was "overwhelmed" after an "emotional rollercoaster" and she said Mrs May had been "incredibly brave" to "stand up" to the US.
Mr McKinnon, 46, admits accessing US government computers but claims he was looking for evidence of UFOs.
The US said it was "disappointed" with Mrs May's decision.
"We note that the home secretary has described this case as exceptional and, thus, this decision does not set a precedent for future cases," said Rebekah Carmichael, of the US Department of Justice.
"At the same time, we are pleased that the home secretary has accepted the finding of Sir Scott Baker's independent panel that the US-UK extradition treaty brings benefit to both countries.
"The United States fully agrees with the report's conclusion that the treaty is fair and balanced."
Mr McKinnon, from Wood Green, north London, who has been diagnosed with Asperger's syndrome, a form of autism, faced 60 years in jail if convicted in the US.
But Mrs May said Mr McKinnon was "seriously ill" and his was a "difficult and exceptional case" and there was a real risk of him attempting suicide if he was sent to the US.
Ms Sharp said her son could not speak when he first heard of the decision but then he cried and hugged her.
She said: "He felt like he was a dead person. He had no job, he didn't go on holiday... he felt worthless."
His solicitor, Karen Todner, said it was "a great day for British justice" and his barrister, Edward Fitzgerald QC, said Mrs May had been "brave".
Mr McKinnon's bail conditions, imposed since 2005, have now been lifted, meaning he can once again use a computer and also access the internet.
Earlier Mrs May told the House of Commons:
- It was now for the Director of Public Prosecutions, Keir Starmer QC, to decide whether Mr McKinnon should face trial in the UK.
- The sole question for her had been whether Mr McKinnon's extradition to the US would breach his human rights.
- There was no doubt he had Asperger's syndrome and suffered from depressive illness, and that there was a risk of suicide if he was extradited.
- Measures would be taken to enable a UK court to decide whether a person should stand trial in the UK or abroad - a so-called forum bar.
Downing Street said Mrs May informed the prime minister about her decision before Wednesday morning's Cabinet meeting. A spokeswoman said: "It's entirely a home secretary decision, she's acting in a quasi-judicial role... and he (David Cameron) supports that decision."
BBC legal correspondent Clive Coleman said it was a dramatic decision - the first time a home secretary had stepped in to block an extradition under the current treaty with the US.
Shami Chakrabarti, director of civil rights group Liberty, congratulated Mrs May and told Radio 4's Today programme: "It is a great day for compassion and common sense.
"This is a man who never left north London, let alone the country.
"Take a look at Gary - he could be anyone's son or daughter in this country and the only bit of law that could save him yesterday was the human rights act."
Mark Lever, chief executive of the National Autistic Society, said: "We've started to raise the profile of the vulnerability of people with autism in the criminal justice system."
Mr McKinnon's MP, Conservative David Burrowes, said: "It's a life that's been given back to Gary in a long dark tunnel that is 10 years. This must never happen again."
But Labour former home secretary Alan Johnson criticised the decision and claimed Mrs May had made a decision which was "in her own party's best interests but it's not in the best interests of this country".
He said: "Gary McKinnon is accused of very serious offences. The US was perfectly within its rights and it was extremely reasonable of them to seek his extradition."
American extradition expert Douglas McNabb said the US Attorney's Office would be furious.
Mr McNabb said he suspected it would ask Interpol to issue a red notice - making other nations aware there was an outstanding arrest warrant for Mr McKinnon in the US - which would mean he could be arrested if he left the UK.
At a press conference Ms Sharp praised the media, and especially the Daily Mail, for campaigning on behalf of her son.
Asked about the possibility of him facing a trial in the UK, she said: "He's lost 10 years of his life, but if this happens as well, we can deal with that."
The family of terror suspect Babar Ahmad said while they welcomed the decision not to extradite Mr McKinnon, questions had to be asked.
Mr Ahmad was one of five terror suspects, including radical cleric Abu Hamza al-Masri, extradited to the US earlier this month. His co-accused, Talha Ahsan, who was also extradited, was diagnosed with Asperger's in June 2009, according to a European Court of Human Rights judgement.
Mr Ahmad's family said: "Why within the space of two weeks, a British citizen with Asperger's accused of computer-related activity is not extradited, while two other British citizens, one with Asperger's, engaged in computer-related activity are extradited. A clear demonstration of double standards."
US authorities have described Mr McKinnon's actions as the "biggest military computer hack of all time" and have demanded he face justice in America.
They insisted his hacking was "intentional and calculated to influence and affect the US government by intimidation and coercion".