Conservative Anglican churches in developing countries will meet next week to consider radical action over the Church of England’s decision to bless same-sex couples in civil marriages, saying they question the archbishop of Canterbury’s “fitness to lead” the global church. The Global South Fellowship of Anglican Churches (GSFA), which represents churches in 24 countries and provinces including Nigeria, Kenya, Uganda and Rwanda, said the C of E’s new stance “goes against the overwhelming mind of the Anglican Communion”. The “reality” of the C of E’s decision was a rejection of the doctrine that marriage is the lifelong union of a man and a woman, it added. On Monday a dozen key church leaders from the global south are expected to consider moves to take a dominant position in the Anglican Communion, relegating Justin Welby, who as archbishop of Canterbury heads up the global church of 85 million people, to a marginal role. In an effort to prevent an irreparable breakdown, Welby has said he personally will not bless same-sex marriages. But conservative church leaders have warned of profound repercussions after the historic vote by the C of E’s governing body, the General Synod, on Thursday. Samy Fawzy Shehata, the archbishop of Alexandria in Egypt, told the synod that “crossing this line of blessing same-sex unions will alienate 75% of the Anglican Communion” and “lead eventually to impaired and broken communion”. He urged the C of E to not “surrender your unique position as the mother church of the Anglican Communion.” Stephen Kaziimba, the archbishop of Uganda, said in a statement on Friday: “God cannot bless what he calls sin. The C of E has departed from the Anglican faith and are now false teachers.” Ahead of the synod vote, archbishop Justin Badi Arama, the head of the Anglican church in South Sudan, said Welby was “failing to defend biblical truth”, and his role as moral leader of the global church had been “severely jeopardised”. Henry Ndukuba, the primate of the massive Nigerian church, was due to meet his bishops on Friday to discuss their response. Gafcon, a coalition of conservative churches, said the C of E had “authorised the blessing of sin” and was “moving a step at a time to fully accept the practice of homosexuality as part of the life and the practice of the English church”. The GSFA, which claims to represent 75% of the global Anglican church, said it would take “decisive steps towards resetting the Anglican Communion”. Its members would not leave the global church but “with great sadness must recognise that the C of E has now joined those provinces with which communion is impaired”. Conservative churches have already broken off relations with churches in the US, Canada, Brazil, New Zealand, Scotland and Wales, which offer church weddings to same-sex couples or bless their civil marriages. During the synod debate, Folli Olokose, a Nigerian-born vicar in the diocese of Guildford, said a vote in favour of blessing same-sex unions would be “putting a nail in the coffin of the Anglican Communion”. Martin Warner, the bishop of Chichester, warned that equal marriage would “undermine trust within the Anglican Communion and be seen in some of the poorest countries of the world as a new imperialism”. Welby has put the global Anglican church at the heart of his leadership of the C of E. He has visited all member churches around the world, some several times, since being appointed archbishop of Canterbury 10 years ago. Unlike the C of E, whose congregations are shrinking year by year amid official data showing that Christianity is now a minority faith in England, churches in the global south are growing rapidly in size and influence. At the synod, Welby came close to tears when he acknowledged that the C of E blessing same-sex unions could put Anglicans in some countries at serious risk. “People [will] die, women [will] be raped, children [will] be tortured … This is not just about what people say, it’s what they’ll suffer,” he said. “I beg you to believe that there’s nothing in my life or heart or prayers that comes as high as the safety and flourishing of people I love in the Anglican Communion.”