Major changes will be made to a document which was set to ask worldwide Anglican bishops to oppose same-sex marriage at a key conference, it is believed.

A spokesman for this week’s Lambeth Conference, which is held once every decade, said there will be a revised text of a draft “call” about marriage which had sparked outrage.

Among the “calls”, which at the conference are similar to motions, the 650 bishops and archbishops from around the world were set to be asked to consider reaffirming a position that “upholds marriage as between a man and a woman”.

The draft call on human dignity also stated that “legitimising or blessing of same-sex unions” cannot be advised and “it is the mind of the Anglican communion as a whole that same-gender marriage is not permissible”.

This was met with fury, frustration and annoyance from many Anglicans since the draft calls were published last week.

It is believed that tweaks have been made to a few of the calls but the one on “human dignity” has prompted the most debate and it may see substantive changes.

Earlier this week bishops of the Church in Wales said the draft text “undermines and subverts the dignity of an integral part of our community, rather than affirming them.”

It added: “Recognising that some provinces will want to affirm the historic understanding of marriage, we wish to assure our LGBT+ sisters and brothers in Christ that we will work to amend this passage to reflect more adequately our understanding of their equal place in the Church”.

The Dean of Southwark Andrew Nunn said: “What really angers me is not the homophobia apparent in all of this, I am used to that, sadly.

“What gets me is the scandalous way the ‘church’, whoever, whatever that is, displays such a lack of openness, transparency and honesty with the rest of us who are the church.”

He said that none of this had been mentioned at the General Synod and he is still waiting for the “open conversations we have all been invited to have which will help us move on even further in our understanding of each other around the subjects of sexuality and committed relationships”.

A group of senior Anglicans have also written to the Archbishop of Canterbury Justin Welby, who is the conference president, the archbishops and bishops of the Church of England to express their “grave concern” about the call and it implications.

The Canterbury-based Lambeth conference of worldwide Anglican bishops runs to August 8.

It is being staged at a time when there is a profound diversity of views across nations and the conference is seen as an attempt, once in a decade, to gather people together to listen and find some common ground.

Many Anglican churches hold to a traditional view of marriage but there are also a growing number of liberal churches who have adopted same-sex marriage.

It appears that, as the event is being staged in a spirit of listening and the bishops, particularly from those liberal provinces, have made their views very very clear in recent days that the conference has been forced listen and respond.

In a statement Bishop Tim Thornton, chairman of the Lambeth Calls Subgroup, said: “Over recent days we have listened carefully to the responses of bishops to Lambeth Calls: Guidance And Study Documents that was released last week and especially in relation to the draft call on human dignity.

“The drafting group for the call on human dignity will be making some revisions to the call.

“This will be published as part of Lambeth Calls which will be the texts that will be discussed by bishops at the conference.”

He added that details of the changes have yet to be made available but the bishops are now to be given the option “to clearly state their opposition to a particular call” when they are discussed at the conference.