With an almighty row looming over sexual morality, the Lambeth Conference of Anglican bishops worldwide looks set to make the recent ructions in the Conservative Party look like a teddy bears' picnic at the vicarage.

Orthodox bishops involved in planning Lambeth 2022 have somehow succeeded in getting a reaffirmation of Lambeth Resolution 1.10, which the 1998 conference passed 'rejecting homosexual practice as incompatible with Scripture', on the agenda for the conference taking place in Canterbury from July 26 to August 8.

The bombshell is there in the 'Lambeth Call on Human Dignity', due to be debated by 650 bishops from the Anglican Communion's member churches (or provinces) across around 160 countries.

Previous Lambeth Conferences passed resolutions but Archbishop of Canterbury Justin Welby, who is hosting the conference, has replaced them with Lambeth Calls to reflect the fact that whatever the attending bishops vote for is not binding on the Anglican Communion's 42 self-governing provinces.

In the Lambeth Calls Study Document circulated to the bishops, the section on human dignity as currently drafted has them calling for "the reaffirmation of Lambeth 1:10 that upholds marriage as between a man and a woman and requires deeper work to uphold the dignity and witness of LGBTQ Anglicans".

But the most controversial part of the Call appears in one of its affirmations: "It is the mind of the Anglican Communion as a whole that same gender marriage is not permissible. Lambeth Resolution I.10 (1998) states that the 'legitimizing or blessing of same sex unions' cannot be advised. It is the mind of the Communion to uphold 'faithfulness in marriage between a man and a woman in lifelong union'."

When the story of 'Lambeth 1.10 Hasta la vista, baby' broke last week, the bishops of the Scottish Episcopal Church (SEC), which allows same-sex marriages, were quick on the draw with a statement: "Human Dignity features as one of the topics, the call for which includes a reaffirmation of the 1998 Lambeth Conference resolution I.10 and defines marriage as permissible only between a man and woman. The wording of that call does not represent the position of the Scottish Episcopal Church as reflected in the Church's Canons, which recognises that there are differing understandings of marriage in the SEC."

The bishops of the Church in Wales, which last year voted to allow same-sex blessings, issued a more strongly-worded statement: "We have noticed a short text, inserted in the draft Lambeth Call on Human Dignity, which undermines and subverts the dignity of an integral part of our community, rather than affirming them.

"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 Church of England issued an ambiguous statement from the nine bishops on the Living in Love and Faith (LLF) Next Steps Group chaired by the Bishop of London, Sarah Mullally.

They said the Call's "affirmation of the Lambeth Resolution 1.10 (1998) that same sex unions cannot be legitimised or blessed will be deeply troubling and painful for some (in the Church of England) whilst offering welcome reassurance to others".

Bishop Tim Thornton, chair of the Lambeth Calls Subgroup, has already said that the wording of the Human Dignity Call will be changed: "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. This will be released as soon as it is available."

Bishop Thornton's subgroup surely faces a hard task in getting rid of the reference to Lambeth 1.10. Even if they succeed, they would face strong pushback from orthodox bishops in the Global South Fellowship of Anglican Churches (GSFA) representing 25 provinces of the Anglican Communion.

Their chairman, the Archbishop of South Sudan, Justin Badi Arama, has released a video saying the GSFA's "clarion call to biblical faithfulness" at Lambeth 2022 "will mean seeking the reaffirmation of Resolution 1.10 of Lambeth Conference 1998 as the official teaching of the Anglican Church on marriage".

Given the strong feelings on both sides of the divide over Lambeth 1.10, the battle over sexual morality at Lambeth 2022 is poised to be fierce. If Archbishop Welby is hoping for a back-patting episcopal fraternal in the halls, corridors and tearooms of the University of Kent, he is facing grave disappointment.

Julian Mann is a former Church of England vicar, now an evangelical journalist.