Sharia law in Britain

Through out Britain there are dozens of sharia courts or councils established in mosques, Islamic centers and schools. These courts have no basis in British law and hold no legal binding; however, with the growing number of British Muslims wishing to follow Islam the need for and use of these councils are growing.
For example, an Islamic marriage is not recognised by British law and therefore many couples will have two ceremonies - civil for the state, and Islamic for their faith. "Dr Hasan, who has been presiding over sharia courts in Britain for more than 25 years, argues that British law would benefit from integrating aspects of Islamic personal law into the civil system, so that divorces could be rubber-stamped in the same way, for example, that Jewish couples who go to the Beth Din court have their divorce recognised in secular courts."
I generally am opposed to the idea of of sharia courts or the establishment of any court outside of a countries national laws. However, in the area of personal law, I can see how beneficial it may be.
The article makes an interesting distinction between the various aspects of sharia law, worship, personal law and penal law. "Penal law is the duty of the Muslim state - it is not in the hands of any public institution like us to handle it. Only a Muslim government that believes in Islam is going to implement it. So there is no question of asking for penal law to be introduced here in the UK - that is out of the question."
The question remains for me, how far? How much leeway should the sharia courts have in British society? And what of Dhimmitude, the relationship of Muslims and non-Muslims at the theological, social, political and economical levels?