Yes but the situation here isn't a handing over is it really? This isn't/won't be an extradition.

If the US were to arrest him on arrival when they have pretty much inferred he has nothing to fear, that would be something else. I would hope regardless of ethnic origin that the UK government would do everything in its power to have the citizen released.

I'm not really clued up on the Northern Ireland conflicts, I do however find the idea of locking people up without trial and keeping them detained for long periods of time, barbaric, regardless of what they are accused of.