Gary McKinnon's legal team has pledged to continue to fight the self-confessed hacker's extradition to the US, after home secretary Alan Johnson refused to step in.
The team will apply to the High Court to seek a judicial review of Johnson's decision, and the application will focus on whether the minister was right to say he was legally unable to intervene, McKinnon's solicitor Karen Todner told ZDNet UK.
"We'll be saying that Alan Johnson has not exercised his discretion properly," she said on Friday.
Todner said that under normal circumstances, parties would have three months to apply for judicial review, but that Johnson had given McKinnon's lawyers a week.
"We have seven days to lodge the issue with the High Court, and expect an expedited hearing before Christmas," she said."[Johnson is] insisting to the High Court that the case be dealt with expeditiously."
If the judicial review application is unsuccessful, the defence team will apply for McKinnon's case to be heard by the European Court of Human Rights (ECHR). It will also request that McKinnon's extradition be stopped until the European court makes its decision.
Johnson broke the news of his decision to Todner in a letter sent on Thursday. In a press statement on Friday, the home secretary said the additional psychiatric evidence presented to him to show McKinnon was at risk of suicide did not indicate that extradition would breach McKinnon's human rights.
"I have carefully considered the representations in the case of Gary McKinnon," Johnson said in the statement. "I am clear that the information is not materially different from that placed before the High Court earlier this year and does not demonstrate that sending Mr McKinnon to the United States would breach his human rights.
"As the courts have affirmed, I have no general discretion. If Mr McKinnon's human rights would be breached, I must stop the extradition. If they would not be breached, the extradition must go ahead."
If McKinnon is extradited and given a custodial sentence in the US, the British government will progress "at the earliest opportunity" any application for the Londoner to serve the sentence in the UK, Johnson said. He insisted that McKinnon will not be incarcerated in a 'supermax' prison in the US, which the defence team has maintained is a possibility.
Todner said McKinnon, who has Asperger's syndrome, was "devastated" by Johnson's decision, and was being monitored to mitigate the risk of suicide.
"He's horrified and devastated, and very flat," she said. "He's on medication and is having ongoing psychiatric treatment."
Janis Sharp, McKinnon's mother, said that the extradition treaty the UK has with the US was not being used to hasten extradition of terrorists and serious criminals, as it was originally intended.
"The only people who won't get extradited are terrorists who face the death sentence, the very people this act was meant to be about," said Sharp in a statement on Friday. "What bitter irony, Alan Johnson and this government should hang their heads in shame to force a peaceful, vulnerable, misguided UFO fanatic like Gary thousands of miles away from his much-needed support network."
McKinnon is accused of accessing military networks, including those belonging to Nasa and the Pentagon, in 2001 and 2002. US prosecutors allege that McKinnon caused $700,000 (£400,000) damage, including disabling a battleship. McKinnon has never denied hacking the systems, but insists he was looking for evidence of extraterrestrial life, and denies causing damage.