[furyg3]

That spying is the status quo is not really the concern of a UK court. In this case, the court does not care about whether or not agents in the UK were breaking US law, or even if there is some treaty between friendly nations to give them immunity. Well they may care, but this is a separate matter.

The court is faced with an extradition request, which will hinge on questions such as: are the charges well laid out and supported? will the defendant get a fair trial? and does this fit within our extradition treaty?

That second point - getting a fair trial - is heavily undermined if there is evidence the US government has privileged information that came from spying.