Maybe this guy could tell you.
Actually because of political infighting, new judges have not been appointed and existing judges are horribly overworked, leading to mistakes and delayed justice.
Also, from a UK/EU standpoint, sentences are much harsher than are traditionally applied here. I grant that the US population is free to do what it likes in terms of its sentencing policy, but that policy makes it a hard sell over the pond.
The solution to this would be simple, and that would be for McKinnon to stand trial in the US but be subject to UK sentencing levels for his alleged offences if found guilty. I believe its already a policy for prisoners to spend their sentences in jails of their home country, so a little diplomacy about the general issue could bring about a system where justice and public opinion is served.