The past scratching of backs.
In any case, the charges of soliciting to murder and inciting racial hatred were not going to result in a sentence that would keep Hamza off the streets long enough to appease the papers that were demanding his deportation. The Americans stepping into the breach was therefore incredibly helpful. It also followed the pattern of the time, where the authorities massively preferred just getting rid of extremist clerics, such as the on-going attempts to deport Abu Qatada, as well the declaration that Omar Bakri Muhammad's presence was not conducive to the public good, rather than going through the frightful process of proving that they had actually committed criminal offences.
Whether Babar Ahmad was directly involved in the discussions around the extradition of Hamza or not we don't know. While it's clear that we ourselves were interested in him, as it takes quite a lot for MI5 to install a bug in your house, it also rather puts charges in doubt when the arresting officers are accused of brutality, allegations that the Met paid out over but which the officers themselves were subsequently cleared of any wrongdoing over, the jury uninformed of the damages. In any event, the CPS again decided there was insufficient evidence against Ahmad, and the US once again came to the rescue. While the charges against Hamza are fairly detailed, they're flimsy at best against Ahmad, especially on whether or not any offence was committed in the US at all; Azzam.com was hosted in the US, but this was when law over jurisdiction on the internet was still developing, while the other charge of Ahmad having a disc in his possession with the movement times of the US fifth fleet through the Strait of Hormuz is laughably thin.
There's also a double standard an inch thick running through the indictment over Azzam.com. It's all well and good for the likes of Evan Kohlmann to describe it as one of the most important jihadist propaganda sites, and crucial for the building of consciousness over the insurgencies in Chechnya and Bosnia, which it was, but it's also the case that without it there now wouldn't be as many of these private security companies and experts like Kohlmann to pontificate on how dangerous those running them are or were. Ahmad doesn't deny that he himself fought in Bosnia, and was supportive of the other insurgencies going on prior to 9/11; the real issue should be whether what he was doing was a crime in this country at the time. The CPS decided there wasn't enough to put before a jury.
All this said, the ECHR was never going to block extraditions to the US, barring all five of those challenging being subject to the same treatment as say, Bradley Manning was. However ghastly the super-max prisons are, and the ECHR in its ruling seems more inclined to believe the authorities than the critics, there wasn't much chance the conditions were going to amount to inhuman or degrading treatment. The ECHR have though quite rightly adjourned their decision on Haroon Rashid Aswat until they've had further assurances on the treatment those with mental health problems receive, as Aswat is currently being held at Broadmoor. Much as you can't begrudge Ahmad going down every avenue, Hamza on the other hook won't be held at a super max as they can't deal with the fact he's an amputee, which rather brings the ECHR into disrepute. Lawyers: the ECHR needs as much help as it can get at the moment, so please don't do the work of the tabloids and Tory backbenchers for them. Thanks in advance.