Are you saying that you weren't aware of this beforehand? That would surprise me. AFAIK, our allies have always spied on us, and vice versa. I would imagine it's not quite as cutthroat, though.
Oh, I don't know about that ... not if "Spooks" is anything to go by.
(I know that's fiction, but I don't know anyone with real life experience of (counter-)espionage.)