Well, the question itself is a rather silly one…but as so many people still ask it here is a brief posting on the issue, linking to resources I have put out elsewhere.
I recently did a video-cast on some questions around British Muslim identity, that can be seen below:
I also wrote about the subject a few years ago in a book called, British Muslims Between Assimilation and Segregation (2003). The pdf of that chapter can be downloaded for free here:
Although some of the arguments may be outdated now and some of my views may have changed over the years, the bulk of the content should give some background to my thoughts on the subject.