Liberal Judaism, the Quakers, and the Unitarians all want the right to conduct Civil Partnerships with religious language in their meeting places. Actually, for Unitarians, it comes down to individual congregations, and I was involved in a congregational meeting that said yes to an enquiry about a necessarily 'private' partnership ceremony, but the (advisory) General Assembly has long taken a line against discrimination. Newington Green Unitarian church has taken a campaigning view about this imposed discrimination, such that it won't carry out weddings with registrars.
Some worthies have written to The Times in support of the three small bodies and their wishes, including the author of the fantastic History of Christianity Diarmaid MacCulloch, Professor of the History of the Church, Oxford, who understands rather a lot about the earliest history of civic and religious pluralism from Transylvania to Lithuania as the left wing of the Reformation broke out before Roman Catholic reassertion. The Unitarianism and Socinianism of the early 1600s was a model for later Western society - toleration.
There are warmly tolerant comments on Thinking Anglicans on this issue. The Bishops of Winchester and Chichester have no grounds for telling the Unitarians or any other religious group what to do, on the spurious basis that Anglican independence is threatened. Yes, trample over others' independence while preserving their own privilege. All they are doing is making the argument for scrapping their place in the House of Lords, because this is indeed privilege and they have abused it. After all, having creedless Unitarians and Quakers, and progressive gatherings of Jews, might also put pressure on the observance of the Trinity and doctrine; are they going to legislate about that? Once they did.
The discrimination the Church of England applies to its ceremonies and ministry is itself being tolerated. It cannot discriminate when it comes to general public employment, just as no public house or club rules can say "no blacks". Even the racist British National Party has made that legal change. The legal toleration preserves discrimination for what it regards as sacred in its own sphere, and thus it will only be required to marry heterosexual couples where one person lives in a parish.
Of course it puts the Church of England out of step. But then the Church of England should not be required to marry any heterosexual couple in a parish - that should be for it to decide. If it wants to, then good. The idea that Church business is the business of national law ought to be cut out. It only ought to be within the law.
Thus the argument for continued establishment is very weak. This is magnified when only one serving bishop has put his name to the list (David Stancliffe). Where, for example, is the name of the so-called progressive Bishop of Lincoln, President of the Modern Churchpeople's Union? Once again: hiding. Well, collective bishops' responsibility is something that the Church of England can have for itself: it is nothing to do with other Churches or faith groups and all this does is spread the guilt. He should not be in the House of Lords either; none of them should be there.
This anomaly of establishment has been amply demonstrated by the bishops interfering by legislation in the wider religious life of the country.