Rowan Williams and sharia law | openDemocracy

He also points out that there is already provision in English law for Jewish and Christian communities to have some autonomy over the governance of their religious affairs, without thereby putting themselves outside the law.

From what I can see, Williams only referred to Orthodox Jewish practice, though. On that, here is a source from the time of the controversy:

BBC NEWS | UK | Religious courts already in use

...Jewish courts are in daily use in Britain, and have been for centuries.>

British Jews, particularly the orthodox, will frequently turn to their own religious courts, the Beth Din, to resolve civil disputes, covering issues as diverse as business and divorce.

...Both sides in a dispute must be Jewish, obviously, and must have agreed to have their case heard by the Beth Din. Once that has happened, its eventual decision is binding. English law states that any third party can be agreed by two sides to arbitrate in a dispute, and in this case the institutional third party is the Beth Din.