At an appeal hearing this week his lawyers argued that McKinnon's human rights were breached by a plea bargaining process instigated by US authorities. They will make the same argument to Home Secretary John Reid if he loses his current appeal.
"The Secretary of State has an inherent discretion to consider someone's human rights under the new Extradition Act," Karen Todner, McKinnon's solicitor, told OUT-LAW.COM. "We are now going to go back to the Secretary of State and ask him to reconsider his position in relation to Gary."
Todner said that the Home Secretary could over-rule the courts and prevent McKinnon from being extradited to the US on the basis of the alleged human rights abuse.
McKinnon is the hacker who broke into the US military and NASA computer systems in 2001 and 2002, where he claims he saw evidence of alien life. McKinnon broke into the systems using just a dial up connection and default passwords.
McKinnon has admitted the offences and said that he wants to stand trial in the UK, but the US has been seeking his extradition, where prosecutors have threatened a jail term of decades.
McKinnon lost his case to resist extradition, and Home Secretary John Reid signed his extradition order last summer. He appealed, and his hearing in the Court of Appeal took place this week.
McKinnon's lawyers introduced an entirely new argument in the hearing, based on a secret plea bargain negotiation that took place in 2003.
"We were contacted by the American authorities and invited to discuss a plea bargain for Gary to go back voluntarily, so not to oppose extradition but simply to go back voluntarily to the US," said Todner. "If he went voluntarily they would allow him to receive a much shorter sentence and they would ensure he would be repatriated to England to serve the rest of his sentence very quickly."
Early repatriation to the UK would be crucial because McKinnon would in that case be eligible for much earlier parole in the UK than in the US. "But they made it clear that if he didn't co-operate that he would receive what they would consider to be a very lengthy sentence and he would not be repatriated," said Todner. The shorter sentence would have been three or four years, but the longer sentence was up to 12 years, she said.
Both parties agreed that the negotiations would never be brought up in court, but Todner said they were introducing it now because she said that the US authorities had used the information in a previous element of the case.
McKinnon's lawyers argued that elements of the plea bargaining process were in fact an abuse of his human rights as laid down by the Human Rights Act. "We argued that that was coercive plea bargaining, that his rights to repatriation and therefore his rights under Article 8 of the Human Rights Act, which is the right to a private and a family life, could be breached because they have already said before he even gets there that he won't be repatriated," said Todner.
"Gary has the right to have his repatriation to this country considered fairly and not arbitrarily and prosecutors have already said that because he objected to the extradition they will not allow his repatriation to take place, and we have argued that that is an abuse of the extradition process," said Todner.
The lawyers cited a precedent from Canada, Cobb v USA, in which US prosecutors were found to have abused the human rights of suspects in Canada by threatening higher sentences for those who did not go to the US voluntarily.
Todner said that even a Canadian case could influence a UK decision. "We're all bound by the Convention on the Transfer of Prisoners, so we do take account of cases abroad, particularly in countries like Canada; we do listen to their cases," said Todner.
The Court of Appeal is expected to announce its verdict soon, possibly next week.