It's hard to imagine Rowan Williams as the succcesor to Thomas Cranmer, the Archbishop of Canterbury who enthusiatically promoted the English Reformation, something for which in the end he paid with his life.
The 1530s were a period of confidence and certainty, the period when England first withdrew from the "European Union", captured by the assertion in Statute in Restraint of Appeals of 1532 that "this realm of England is an empire, and so hath been accepted in the world, governed by one Supreme Head and King".
This is a far cry from the defeatism of Archbishop Williams and his comments about the inevitability of sharia law in England.
In making his comments, Rowan Williams also overlooked one the main underlying causes of the Reformation ie the abuse of the powers of ecclesiastical courts. If he has forgotten this lesson from history, and one of core principles of the English Reformation, then he should seriously ask himself whether he is fit to lead the church born out of that bold assertion of English sovereignty.