The General Synod of the Church of England is today charged with making a historic decision about whether to allow women to become bishops.
The mother church of the 78-million strong worldwide Anglican Communion has been discussing the issue in detail for 12 years now, with the momentum towards change looking inevitable since the established church in England decided to ordain women priests in 1992, and finally did so for the first time in March 1994.
Women now account for a third of the ordained ministry of the Church of England, and many who were originally sceptical of the change have now been won over.
However, a hard core of conservative evangelicals and conservative catholics within the Church have fought a persistent rearguard action, refusing to recognise women as priests and now seeking to do all they can to thwart their road to the episcopal office of oversight.
In July 2012 a vote on a legislative measure to permit women bishops in the Synod, the Church of England's governing body, was postponed due to a disagreement about provisions for opponents -- who want an alternative oversight system which means that they will not have to accept the authority of women.
The worry of proponents is that allowing parishes and clergy to choose an outside male bishop over and against a diocesan female one will continue to make women bishops 'second class'.
Two of the three houses of the General Synod, those of Bishops and Clergy, are expected to achieve the necessary two-thirds majorities in favour. But the lay members' vote could be tight. A vote is expected around 7pm this evening.
A compromise is being considered today which says that a male bishop should be selected in a manner that "respects" the reasons why the parish asked for him. The details of that will be worked out in pastoral guidelines rather than legislation.
This is regarded as an insufficient guarantee by the small minority opposed to women's episcopal ministry, who effectively wish to maintain a 'church within a church' as a male preserve, and who want a right to choose not only a male bishop, but one 'untainted' by support for women's ministry of any kind.
There are a few supporters of women bishops who have also been arguing that a rejection of the compromise in today's vote might enable a better, unsullied proposal to come back onto the table in 2015.
But WATCH (Women and the Church) and others, having consulted widely among supporters, say that the time for action is now, and that the 'guideline' approach to handling those unwilling to accept the ministry of women bishops is better than yet another delay which denies them their vocation to an episcopal role for an even longer period of time, probably into the next decade.
The current Archbishop of Canterbury, Dr Rowan Williams, and his successor elect, Bishop Justin Welby of Durham, are both strongly urging a 'yes' vote.
The discussion in Synod has been going on this morning, with strong speeches in favour from the Bishops of Manchester and Liverpool, among others.
Some one thousand Church of England clergy signed an open letter to the Independent newspaper on Sunday 18 November, setting out the case for change and for the recognition of women's full ministry in biblical terms.
If today's vote goes in favour of women bishops, it has to be proceeded by parliament and then receive the Royal Assent, paving the way for the first woman to be consecrated in 2014 or after.