McKinnon had tried to argue that former home secretary, Jacqui Smith, was wrong in law to push for the extradition despite his diagnosis of Asperger's Syndrome, and that the director of public prosecutions was also wrong to opt for extradition despite having sufficient evidence to prosecute McKinnon here in the UK.
However, Lord Justice Stanley Burnton and Mr Justice Wilkie dismissed both claims on Friday. McKinnon now has 28 days to launch an appeal at the Royal Courts of Justice. According to his solicitor, Karen Todner, McKinnon and his legal team will also appeal to the Law Lords, and Todner has made a fresh approach to President Obama.
"I have today sent a letter to President Barack Obama signed by 40 members of a cross parliamentary group of MPs asking him to step in to bring this shameful episode to an end," Todner said in a statement on Friday. "It is a sad state of affairs if this government cannot protect our most vulnerable of citizens."
In her statement, Todner also referred to the judges' decision as "inhumane" and "an affront to British Justice".
The decision comes almost seven years after McKinnon, from North London, was indicted by the US Department of Justice in November 2002. He was charged with intentionally damaging a federal computer system, and with breaking into 97 computers belonging to the US Army, US Navy, US Air Force, US Department of Defense and Nasa.
McKinnon has never denied the hacks, although his legal team has disputed the cost of the damage he allegedly caused — around $700,000 (£500,000), according to US authorities. The Londoner said he had been looking for suppressed evidence of extraterrestrial life, and pointed out the poor security that had been applied to the affected systems.
The case has had ramifications beyond the hacks themselves, as it has drawn attention to the extradition treaty that exists between the UK and the US. The US can demand a suspect be extradited from the UK without probable cause, but no such arrangement exists in the other direction.
McKinnon has also been diagnosed by the autism expert Simon Baron-Cohen with Asperger's Syndrome, a disorder on the autistism spectrum. If he is convicted in the US, McKinnon faces up to 70 years in a maximum security federal prison, and his legal team has argued that, given his condition, this situation would put him at risk of psychosis or even suicide.
Politicians and celebrities have rallied behind McKinnon, arguing that he should serve any potential sentence here in the UK, rather than in the US.
This article was originally posted on ZDNet UK.