The Church of England would go through a "substantial period of shock" if its national assembly voted against the introduction of women bishops, a senior cleric has warned.
The Rt Rev Peter Price, Bishop of Bath and Wells, said he does not believe the Church of England's bishops had a "plan B" if final approval for legislation introducing female bishops is rejected in July.
"I think the implications of this measure going down are so far-reaching that we almost dare not face it," he told a meeting in London of campaigners in favour of women bishops.
"I think we will be in such a critical place that it is extremely difficult to see how we will proceed without going through a very substantial period of shock. I wish I could say that there was a plan B - I don't think there is."
The Rt Rev Price was speaking as traditionalists and supporters of women bishops prepare to clash again on the subject.
The earliest final approval by the General Synod for legislation would be July with the introduction of the first women bishops in 2014.
The fringe meeting heard from the Rt Rev Rose Hudson-Wilkin, chaplain to the Speaker of the House of Commons, and a vicar in east London, who said she opposed "discriminatory" laws against women bishops.
She urged supporters to lobby MPs over the introduction of the change.
"We want women bishops to be bishops in the same way that men are bishops without any discriminatory laws built in," she said.
She added: "We are called to love but it doesn't mean that we have got to be a mat to be walked over. We need to get that quite clear."
Around 200 supporters of women bishops including the Rt Rev Price gathered for a silent vigil on the steps of Church House in Westminster as the General Synod prepared to open.
The legislation to introduce women bishops will need a two-thirds majority in all the Houses of the General Synod - bishops, clergy and laity - in order to gain final approval in July.
Anglo-Catholics and conservative evangelicals have threatened to vote against the legislation if their demands for safeguards for opponents are not met.