It's interesting that this is posted on a section about a foreign conflict? Perhaps Muslims are aggrieved that the UK isn't paying much attention to the perma conflict that is the middle east?
One issue is that for some Muslims loyalty to a pan global religious following is greater than loyalty to the state and yes that does worry some.
I think it is the slow changing of British culture under continuing immigration and demographic changes that does concern a significant proportion of the UK population and I think that debate has to be had. We can't ignore all the reform voters out there currently and we can see the influence of immigration in the US elections.
Other religions such as Hinduism, Sikhism, Judaism do not seem to bring out debates like this so we have to question why?