I think the Archbishop, Rowan Williams just likes publisity. Even bad is better than none. I was very concered by what he was reported to have said. No way should Sharia law or any part of it be incorporated into the legal system. This applies to all other religious systems as well.
The Archbishop should be standing for Christianity and ensureing it continuance and not trying to encourage other religions.
Is there any Muslim Cleric encouraging Christian values or laws? Endorsing Chrisianity? I would think not.