Gay Christians could go on hunger strike unless the Church of England changes its attitude to homosexual clergy, campaigners have warned.
The threat was made as world Anglican leaders prepared for crisis talks on the appointment of an actively gay bishop in the United States.
Richard Kirker, general secretary of the Lesbian and Gay Christian Movement, said "civil disobedience" was possible.
A Church spokesman said the issue of gay clergy was being debated.
The call for reform was made in an interview with BBC Radio 5 Live a day after the Pope warned Anglicans about homosexuality in the Church.
Meeting the Archbishop of Canterbury for the first time, the Pontiff said "new and serious difficulties have arisen" in relations between the two Churches.
In what was thought to be an indirect reference to gay clergy, the Pope told Archbishop Rowan Williams that Christians had to be protected from what he called erroneous and misguided interpretations of the faith.
The Pope has spoken out over gays in the church
"These difficulties are not all of a merely disciplinary nature; some extend to essential matters of faith and morals," Pope John Paul II said.
But Mr Kirker said activists might consider a range of protests in order to force a change in attitudes.
"There will be some people who consider that civil disobedience of one sort or another is justified as it has been in many other hard-fought struggles for freedom and liberation," he said.
"I think people will probably fast, they will go on hunger strikes, they will place themselves in relation to meetings and services in such a way as to make it absolutely clear that they have got be dealt with."
Mr Kirker's claims are a measure of the rising tension amongst gay Anglicans, BBC religious affairs reporter Martha Doyle said.
They are worried that traditionalists will force the church to take a harder line on homosexuality, she added.
Gay Christians were dismayed when homosexual canon Jeffrey John turned down the post of Bishop of Reading, after his appointment threatened to split the church.