On the basis of he embarassed the most powerful nation on earth, and it's not going to let that stand. They will try to extradite him, and if possible, put him in ADX as an example to all others. Given the UK is basically the US's bitch, if there's any possible legal way to extradite him, they will.

[ADX is a fate worse than death](https://en.wikipedia.org/wiki/ADX_Florence)

&gt;Prisoners spend 23 hours per day in single, soundproof cells with facilities made of poured concrete to deter self-harm, and 24-hour supervision, carried out intensively with high staff-inmate ratios.

When you go in, you literally never see the sun for the duration of your (usually life long) stay. One cell. One "yard" which is completely inside the concrete structure. That's your life.

* 23 hours in your 7'x12' cell. 
* 1 hour in a fenced in "yard" in the middle of the facility.