The Guardian article points out that some aspects of Sharia law are already in practice, as you point out - there's no need to go calling for it if it has already been worked into UK law/practice.  

One of the issue around this debate is that it has been completely distorted - as anything around Islam does.  The response from the Equality and Human Rights Commission talks more widely about the implications of Sharia Law - for example where custody of children in divorce cases is concerned.  

That aside, should there be a clearly visible separate system (whether or not some aspects already exist in practice)?  Do we really want to go so far as to create very clear and separate Sharia law where actually in many cases it is reasonable to adjust UK law and practice so that it becomes able to accommodate some of the needs/requirements of muslims without making a big fuss and a special case about it?  

He probably thinks his "tolerance" for Shariah is progressive in light of the Islamophobia that mars parts of Europe today. But it is a tolerance that condones only the most conservative options for Muslims. It is at best a form of the racism of lower expectations - the cheapest bargaining chip of liberal guilt..............

We must resist selling out women's rights and pandering to fundamentalist religionists

Exactly.

keep to the Fen Causeway

Very powerful article.

It reminded me of the Iranian author Azar Nafisi:

"I very much resent it when people - maybe with good intentions or from a progressive point of view - keep telling me, 'It's their culture' ... It's like saying the culture of Massachusetts is burning witches."

One of the things I will never understand is why some progressives seem more willing to tolerate religious extremists when their religion is oppressed or discriminated against. It does not help their non-crazy co-religionists - quite the opposite, in fact. And I really see no reason to help the fundagelical crazies, no matter which religion they are from.

- Jake

Friends come and go. Enemies accumulate.

But the problem with the article is that, like so many people, she does not seem to have read what the archbishop said in his lecture, but instead media reports of it. While I'm generally against religion, it is important when criticising a text to deal with what was actually written (as in the case of Dawkins' book). Thus, far from supporting the most conservative elements in Islam, he is clearly opposed to what he refers to "Islamic primitivists" and discusses the problems they can create, e.g. for women.  

She asks, sarcastically:

"When the archbishop so generously extended Muslims the right to use Shariah, I wonder whose version of Shariah he meant? The Angel Gabriel did not reveal Shariah to the Prophet Mohammed. Much Islamic law was codified many centuries after the prophet died, by male jurists who came up with laws that met the needs of their time. There are various Sunni and Shiite Muslim schools of thought, but there is no consensus on one version of Shariah."

But, had she read the lecture, she'd know that he was well aware of this:

...while certain elements of the sharia are specified fairly exactly in the Qur'an and Sunna and in the hadith recognised as authoritative in this respect, there is no single code that can be identified as 'the' sharia.  And when certain states impose what they refer to as sharia or when certain Muslim activists demand its recognition alongside secular jurisdictions, they are usually referring not to a universal and fixed code established once for all but to some particular concretisation of it at the hands of a tradition of jurists.
...
To recognise sharia is to recognise a method of jurisprudence governed by revealed texts rather than a single system.  

http://www.archbishopofcanterbury.org/1575

Similarly, despite her suggestion that he is "naive" about the problems women might face, he is clearly very aware of this:

The second issue, a very serious one, is that recognition of 'supplementary jurisdiction' in some areas, especially family law, could have the effect of reinforcing in minority communities some of the most repressive or retrograde elements in them, with particularly serious consequences for the role and liberties of women.
...

Recognising a supplementary jurisdiction cannot mean recognising a liberty to exert a sort of local monopoly in some areas.  The Jewish legal theorist Ayelet Shachar, in a highly original and significant monograph on Multicultural Jurisdictions: Cultural Differences and Women's Rights (2001), explores the risks of any model that ends up 'franchising' a non-state jurisdiction so as to reinforce its most problematic features and further disadvantage its weakest members: 'we must be alert', she writes, 'to the potentially injurious effects of well-meaning external protections upon different categories of group members here - effects which may unwittingly exacerbate preexisting internal power hierarchies' (113).  She argues that if we are serious in trying to move away from a model that treats one jurisdiction as having a monopoly of socially defining roles and relations, we do not solve any problems by a purely uncritical endorsement of a communal legal structure which can only be avoided by deciding to leave the community altogether.  We need, according to Shachar, to 'work to overcome the ultimatum of "either your culture or your rights"' (114).

http://www.archbishopofcanterbury.org/1575

This is not to say that I agree with everything he says, just to show that it is far more complex and considered than most media commentary suggests, including her article.

For a good article on the lecture and the criticism of it see:

http://www.opendemocracy.net/article/faith_ideas/europe_islam/sharia_law_uk

Nowhere in the lecture does Williams call for the implementation of sharia law - though this has become the default assumption underlying the febrile controversy the talk and its accompanying media coverage almost instantly generated. Rather, he asks how it might be possible for the civil law to accommodate some of the legal procedures by which Muslim communities in Britain have traditionally regulated their relationships and financial affairs, while safeguarding the equality and human rights afforded by modern law for vulnerable individuals (particularly women) within those communities.

...
In its conservative versions, Islam does pose a challenge to modern western values, particularly with regard to its treatment of women and its resistance to the idea of religious freedom. Yet the archbishop makes very clear that he rejects any change in the law which would deprive individuals of the rights they are entitled to as modern British citizens; and nowhere does he offer encouragement or affirmation to what he refers to as "Islamic primitivists".

Maybe it's because I'm a Londoner - that I moved to Nice.