In his book Islam in Britain, Patrick Sookhdeo, director of the Institute for the Study of Islam and Christianity, says there is an "alternative parallel unofficial legal system" that operates in the Muslim community on a voluntary basis.
"Sharia courts now operate in most larger cities, with different sectarian and ethnic groups operating their own courts that cater to their specific needs according to their traditions," he says. These are based on sharia councils, set up in Britain to help Muslims solve family and personal problems.
If (or when) gangs of violent youths make it impossible for representatives of the British Government to intervene in Muslim neighborhoods (as it is now impossible for French police in 751 "zones urbaines sensibles," or for Swedish police in some areas of Malmo), then sharia law will be the only law.
In effect, these neighborhoods are no longer part of Britain, but rather, as Daniel Pipes puts it, the more precise name for these zones would be Dar al-Islam, the place where Muslims rule."
A large proportion of the tens of millions of Muslims who have moved to Europe in the past 25 years were not immigrants after all; they are settlers.