Warning long, rambling post, feel free to skip this post

>the state religion in England... C of E ... (everyone is by law presumed a member of it)
Bob, are you trying to tell me that every last person in an entire country is presumed to be a member of one religion???

A difference between UK and the USA is that the Church of England is an "established church". I can't find an exact short definition of what this means but Google on "England Established Church" to get several versions. I'm sure Rhu can fill us in as you have to wade through a lot of history from Henry VIII onwards to get anywhere. Strangely, the Church of England's own website doesn't give an exact definition of the implications today, even though there are regular discussions about disestablishmentarianism.

Since I have not lived through an age when people who were not members of the Church of England were barred from public office it has little impact on daily life, we currently have a Catholic Speaker of the House of Commons, for example, although the accession of a Catholic monarch is still probited by law. http://www.royalreport.com/newscharles1.html

The main use that is made of the Church of England by those who are not regular church goers is as a place to get married. We do not have a long tradition of people marrying in places other than churches (or other places of worship)(although the law recently changed), so a CofE wedding is the norm amongst those are baptised members of the the Church of England or those (eg those baptised in another church) who do not choose to follow any other religion. See: "Entitlement to marry. Any person of British Nationality who normally resides in England is entitled to marry in his or her Church of England parish church, provided that (1) the other partner is also of British Nationality and also normally resides in England, (2) that there are no legal impediments of the kind described below [Section 6], and (3) that neither of the couple is a divorcee whose previous partner is still living (the Church of England's regulation on this matter is recognised in law [Matrimonial Causes Act 1965, s.8] - see below, section 10.1). This entitlement applies irrespective of whether either of the couple normally attends church and irrespective of whether either of them has been baptised. It also applies irrespective of whether either partner is a member of the Church of England, or of another denomination (or of none)"http://www.cofe.anglican.org/lifechanges/index.html

Although the Queen is the head of the Church of England, decisions are made by the Synod. Although bishops sit in the House of Lords and are appointed by the Prime Minister (I think) my understanding is that the Church runs its own affairs and the political stuff is just a rubber stamping exercise. I doubt that a Prime Minister would dare to try to get involved in the real process of selecting a Bishop, although there are plenty of conspiracy theorists who dislike any political involvement in the process.

Here's some current information:
"Almost half of all adults in the UK say they have no religious affiliation, according to a new survey.
The decline in religious belief is most apparent in the Church of England which now claims the loyalties of just over a quarter of the population. ... The report found that 48% of people in the UK claim to belong to a religion, compared with 86% of people in the US and 92% of Italians."
http://news.bbc.co.uk/hi/english/uk/newsid_1043000/1043986.stm

From the Church of England's Website:
"Church of England Weddings
In 1996 there were 71,000 weddings in Church of England churches*. These comprised 27% of all weddings and 41% of all first weddings. In 1995 there were 80,000 Church of England weddings.
Baptised Population
It is estimated that over 25 million people living in England today (about half the population) have been baptised by the Church of England."http://www.cofe.anglican.org/about/frame_organisation.html

Sorry that I couldn't give a shorter answer!

Jo