Rising tensions, misguided hatred for a religion, sanctions on immigration possibly? Depends--British Empire is old--population is a flux (human mortality and all) but the County has a sociological conditioning which goes back a while, not like they haven't seen worse. Britian as a whole acting body comes off to me (a complete outsider), as kind of subdued...if not disillusioned in their actions.
Blame Religion, blame Western Occupation...or just Westerners in general. Both sides are wrong, blame a worthless fucked up third world Country that won't grab hold of it's shit, or simpler yet just blame the cock suckers who did it. Muslims shouldn't be a poison container for the acts of some, just like that British Soldier shouldn't have been a container for some ghetto immigrant thugs.