US prosecutors are on record as wanting to see him 'fry' and his legal representatives are now planning to appeal to the European Court of Human Rights. The unanimous judgment is available online and was written and delivered by Lord Brown of Eaton-Under-Haywood.
The case seems to have hinged on the legal technicality of whether US threats, as part of the plea bargaining that has taken place in the case, would amount to an abuse of process, thereby undermining the validity of the extradition. The Lords used a parallel Canadian Supreme Court case from 2001, USA v Cobb  1 SCR 587, in which the extradition proceedings were blocked, to guide their decision. They distinguished the two cases, effectively saying that the threats in the Cobb case were much more scary and they were made by a judge as well as a prosecutor. The relevant paragraphs from the decision from my perspective were 28-31 and 39-42. It is a relatively short and accessible judgment and it will be interesting to see the ECHR's take on it.
"28. The appellant’s main argument focuses on the wide disparity between on the one hand the predicted likely outcome if the appellant cooperated with the US authorities—a sentence of 3-4 years of which 6-12 months would be served in a low security prison in the US after which there were good prospects of repatriation with the expectation of release after serving only half the sentence—and on the other hand the threatened likely outcome if the appellant refused to cooperate—a sentence of 8-10 years or more in a US high security prison with remission of only 15%. Such a disparity, it is submitted, is disproportionate and subjected the appellant to impermissible pressure to surrender his legal rights, particularly his right to contest extradition. Pressure of this kind, it is submitted, indeed plea bargaining generally, runs flatly counter to the principle of English law recently clarified in the judgment of the five-judge Court of Appeal delivered by Lord Woolf CJ in R v Goodyear  1 WLR 2532: essentially that a judge may respond to a defendant’s request that he be told the maximum sentence that would be imposed on a plea of guilty but is not to volunteer such information unasked nor to indicate what sentence might be passed on the defendant’s conviction by the jury. As the Court stated at para 54: “With some defendants at any rate, the very process of comparing the two alternatives would create pressure to tender a guilty plea.”
29. Where, as here, the respondent government is seeking the assistance of the English courts to extradite an accused, it must, submits the appellant, comply with the legal principles of this jurisdiction. True it is that he has in fact resisted the pressure improperly put upon him but that, he submits, is no answer to the contention that it constituted an abuse of process: it was calculated to interfere with the extradition proceedings.30. For this submission and indeed more generally in support of the abuse of process argument the appellant relies principally upon the judgment of the Supreme Court of Canada in USA v Cobb  1 SCR 587. The USA there had indicted a large number of defendants, including the two Canadian appellants, on mail fraud charges. Many had submitted voluntarily to the Court in Pennsylvania and on sentencing one of them the trial judge had said (p 593):
“I want you to believe me that as to those people who don't come in and cooperate and if we get them extradited and they are found guilty, as far as I am concerned they are going to get the absolute maximum jail sentence that the law permits me to give.”
About a week before the Canadian extradition hearing the American prosecuting attorney was interviewed on Canadian television and said:
“I have told some of these individuals, ‘look, you can come down and you can put this behind you by serving your time in prison and making restitution to the victims, or you can wind up serving a great deal longer sentence under much more stringent conditions’ and describe those conditions to them.”
Asked by the interviewer “How would you describe those conditions?", the attorney replied: “You are going to be the boyfriend of a very bad man if you wait out your extradition". That was understood by the Court to mean that they would be subject to homosexual rape. Asked then: “And does that have much of an impact on these people?", the attorney answered: “Well, out of the 89 people we have indicted so far, approximately 55 of them have said, ‘We give up'".
31. In allowing the appeal and reinstating the extradition judge’s order staying the extradition process, Arbour J, giving the judgment of the Supreme Court, said, at paragraphs 52 and 53:
“By placing undue pressure on Canadian citizens to forego due legal process in Canada, the foreign state has disentitled itself from pursuing its recourse before the courts and attempting to show why extradition should legally proceed. The intimidation bore directly upon the very proceedings before the extradition judge . . . [The judge] was also correct in concluding as he did that this was one of the clearest of cases where to proceed further with the extradition hearing would violate ‘those fundamental principles of justice which underlie the community’s sense of fair play and decency’ (Keyowski  1 SCR 657, 658-659), since the requesting state in the proceedings, represented by the Attorney General of Canada, had not repudiated the statements of some of its officials that an unconscionable price would be paid by the appellants for having insisted on exercising their rights under Canadian law.”...
33. Did the US prosecuting authority here “attempt to interfere with the due process of the Court"? Did it place “undue pressure [on the appellant] to forego due legal process” in the UK and so disentitle itself from pursuing extradition proceedings? Would extradition in this case “violate those fundamental principles of justice which underlie the community’s sense of fair play and decency"? Would the appellant following extradition be paying “an unconscionable price . . . having insisted on exercising [his] rights under [English] law"? These are the questions plainly raised by the Supreme Court’s judgment in Cobb (and by the closely related case of USA v Shulman  1 SCR 616). They are also to my mind the essential questions underlying the single question certified for your Lordships’ determination on this appeal...
39. The differences between this case and Cobb are striking. In Cobb it was the judge who stated that non-cooperation would result in “the absolute maximum jail sentence that the law permits me to give” and he, after all, unlike the prosecuting authority, had the power to pass sentence. And in Cobb the prosecutor, so far from forewarning the defendant of the differing consequences which could be expected to follow (perfectly properly) from his decision whether or not to cooperate, effectively threatened (and here I use the word advisedly) those not cooperating with homosexual rape.
40. The high watermark of the appellant’s case here consists of Mr Lawson’s recollection that, unless the appellant consented to extradition (as opposed merely to pleading guilty if extradited), the prosecuting authorities would oppose his repatriation. That, however, even were it to be regarded as an unlawful threat, has now been expressly repudiated by Mr Wiechering, again in marked contrast to the position in Cobb.
41. In my judgment it would only be in a wholly extreme case like Cobb itself that the court should properly regard any encouragement to accused persons to surrender for trial and plead guilty, in particular if made by a prosecutor during a regulated process of plea bargaining, as so unconscionable as to constitute an abuse of process justifying the requested state’s refusal to extradite the accused. It is difficult, indeed, to think of anything other than the threat of unlawful action which could fairly be said so to imperil the integrity of the extradition process as to require the accused, notwithstanding his having resisted the undue pressure, to be discharged irrespective of the strength of the case against him.
42. In my judgment this is far from being such a case and accordingly I would dismiss the appeal."
There you have it. They considered one question: did the plea bargaining threats - to call for a more severe sentence to be served entirely in a US prison by compared to a shorter sentence during which the defendant would be repatriated to the UK to serve the latter part of his sentence - amount to an abuse of process. Their Lordships thought no, taking into account the fact that the US prosecutor who allegedly made the threats denied having done so. Gary McKinnon's supporters are, needless to say, disappointed with the decision.