Liberal members of the House of bishops could launch a protest on the floor of the general Synod in York.
The Archbishop of Canterbury is facing and unprecedented rebellion from bishops in the Church of England who are demanding that he and the Archbishop of York withdraw controversial plans to undermine the authority of women bishops.
Liberal members of the House of Bishops at the General Synod in York have privately warned Dr Rowan Williams and Dr John Sentamu that they will try to sabotage the Archbishops' proposal on the floor of the synod if the Archbishops do not withdraw it.
A planned rebellion on something of this order is almost unknown, but Dr Williams detests being put under pressure to act against his conscience. Traditionalists are protected by his amendment because it gives them the chance to opt for a separate episcopal jurisdiction "untainted" by the hands of a woman bishop, thus taking away some of the usual jurisdiction from the woman.
Critics of Dr Williams and Dr Sentamu say that the number of women and their supporters who will be offended if the amendment succeds is far greater than those who will be offended if it fails. While women are unlikely to leave the Church, believing still in the possibility of transformative change, the issue threatens to make the Church of England appear so absurdly misogynistic that, combined with the fall-out over the failure to appoint Dr Jeffrey John as Bishop of Southward, any new Christians will be deterred from joining the Anglican Church.
If Dr Williams and Dr Sentamu refuse to withdraw their amendment, which will be debated towards the end of the 19 hours of debate this weekend on legislation to ordain women bishops by 2015, the bishops are threatening to vote against it.
If they are successful in defeating the amendment, Dr Williams will be under strong pressure to resin. Even if he clings on, his authority and credibility may never recover from the double debacle of defeat over women bishops and humiliation over Dr John, the Dean of St Albans.
General Synod delegates are elected to a five-year term that includes yearly General Synods. That means if the measure is defeated the Church of England may not revisit women bishops for decades.