Dr Michael Nazir-Ali, the former bishop of Rochester, warned on Tuesday that a move to celebrate same-sex relationships in church would be a “red line” for traditionalist parishes.
Clergy and lay members of the Church opposed to any relaxation of the rules could reject the authority of any bishops who supported the move, he warned.
His intervention came amid mounting expectation that an official commission examining the Church’s teaching on sexuality will recommend the introduction of a formal service for gay couples.
Dr Nazir-Ali said: “If there is an attempt to provide for blessing of same-sex unions that will be a red line for many people.
“Indeed it may be a red line for some bishops, dare I say.”
Speaking after attending a gathering of more than 1,300 traditionalist Anglicans in Kenya earlier this month, Dr Nazir-Ali said the introduction of formal blessings for gay couples would amount to the Church’s leadership failing people who want to “maintain orthodoxy in the faith”.
Following this month’s summit, organised by the influential Global Fellowship of Confessing Anglicans (FCA), a statement backed by 331 bishops urged parishes who believed the Church was undermining “biblical faithfulness” to consider withdrawing their funding.
It warned that “homosexual practice” was being promoted as “holy” despite being against traditional Church teaching.
“We want to make clear that any civil partnership of a sexual nature does not receive the blessing of God,” the statement added.
The intervention by the traditionalist leaders came as a commission examining the Church’s approach to sexuality is due to report to the Church’s house of bishops within weeks.
The review, chaired by Sir Joseph Pilling, a former mandarin, and including four bishops, has taken place amid growing tension over the Church’s approach to gay worshippers and clergy.
The Church’s leadership, including the Archbishop of Canterbury, the Most Rev Justin Welby, objected to the Government’s introduction of same-sex marriage, on the basis that the move conflicted with traditional teaching.
In response, campaigners warned that bishops would have to respond “more sensitively” to gay couples who could not get married in church.
Senior bishops have since questioned whether it was still tenable for the Church to deny a formal blessing to gay couples.
On Tuesday night the Rev Colin Coward, the director of Changing Attitude, a campaign group which represents more than 1,000 Anglicans, said it was apparent that bishops supported a change because many “tacitly” allowed informal blessings of gay couples to take place in their dioceses.
Another priest, the Rev Peter Ould, claimed on his blog that the final draft of the report was ready and “will propose that the Church of England introduce some form of liturgy that will bless same-sex relationships.”
However, one senior figure in the Church said there would be opposition to new liturgy for same-sex couples.
Such a move would amount to a “major shift” in Church teaching, he said.
He voiced doubts that if the Pilling Commission does recommend a new service that the House of Bishops would adopt it, let alone the General Synod, the Church’s parliament.
All of the five most senior clerics in the Church of England – the Archishops of Canterbury and York and bishops of London, Durham and Winchester are from traditionalist wings of the church.
However, Archbishop Welby has spoken repeatedly about the need for the Church to face up to a “revolution” in attitudes to sexuality.
Last year the Church’s leadership lifted a blanket ban on anyone in a civil partnership becoming a bishop.
Colin Hart, head of the Christian Institute, a traditionalist group, said: “If the Church blesses same sex unions it will have abandoned core Christian teaching about marriage and human sexuality.”
A Church of England spokesman said: “The final draft of the Pilling report has not yet been completed or signed off. It will be going to the House of Bishops in December.”