Muslim rule???
Granted all religions have a place in the world its down to each person to make up their own mind on who they believe in etc, yes there have been acts under taken by many believers in separate religions to prove a point or in protest (Vietnam Buddhist priest as possibly the most famous pictorial evidence).
Its learning to get along amongst ourselves and respect other peoples beliefs that is paramount regardless, war in the name of religion is pathetic, not one of the holy scriptures be it catholicism or islam condone war or human cruelty.
As for places being under specific rule of one religion, well that is true to say in any country in any part of the world, in california im sure there are areas with a vast majority of scientologists!
And as for religious law governing certain parts of the UK, that does not mean they are exempt from local laws.

Just my 2 pence worth (for people not sure of the word pence its a monetary value of the UK)