The Church of England has already liberalised on human sexuality and a split is "almost certain" as a result, according to a damning article from a conservative theologian.

Dr Joe Boot, Wilberforce Director at Christian Concern, has given a withering assessment of the Archbishop of Canterbury's recent address to the Church's governing body and wrote the "conversation on these terms is already over".

"What the Anglican Church's 'conversation' is engaged in... is the attempted rationalisation of sin in order to alleviate the reality of guilt which all those practising sexual immorality feel."

The Church of England is in an ongoing process of what it calls "shared conversations" to discuss different perspectives on acceptance of homosexuality and "help forge better understanding between different groups over the issue of sexuality", according to Archbishop of York John Sentamu.

However Sentamu denied the Church is "poised to rethink its centuries-old doctrine of marriage to accommodate same-sex couples", in a letter to The Telegraph.

But Boot argued the position has already subtly moved and a split is inevitable.

"The truth is that once you have accepted, as the Archbishops clearly do, that "LGBTI" et al. is a real matter of human identity, rather than mere social construction, any denial of the normative character of their actions becomes a denial of 'human rights' and an assault on their dignity and person and consequently is 'homophobic,' 'transphobic' or any other number of regularly enumerated mental crimes and disorders."

He also said the "bishops' uncritical adoption of the language of Queer theory" meant a change in the Church's teaching on homosexuality was "already essentially resolved".

Boot is a theologian and apologist as well as founding pastor of Westminster Chapel in Toronto and founder of the Ezra Institute for Contemporary Christianity (EICC). He also has a role within UK Christian public policy charity, Christian Concern, as director of the Wilberforce Academy and Wilberforce Publications.

His intervention comes after Jayne Ozanne, a leading gay evangelical Anglican and member of General Synod, wrote a letter to Welby and Sentamu ahead of the recent gathering of Anglican world leaders at the Primates conference.

Along with 105 Church of England members, Ozanne called for the Church's "repentance for accepting and promoting discrimination on the grounds of sexuality". The signatures said the Church must acknowledge it has "failed in our duty of care to LGBTI members of the Body of Christ around the world.

"We have not loved them as we should, and have treated them as a problem to be solved rather than as brothers and sisters in Christ to be embraced and celebrated. We have made them feel second-class citizens in the Kingdom of God, often abandoned and alone."

However in his article, Boot lambasted Justin Welby for his failure to instil strict "sanctions" on The Episcopal Church in North America who openly endorse same-sex marriages and allow clergy to enter into gay and lesbian unions.

"Justin Welby has been at pains to say that there have been 'no sanctions' applied to the North American church for its heretical position on marriage and human sexuality," he wrote.

"By contrast, St. Paul is abundantly clear that the church is to judge those within it in this matter of sexual immorality, to "purge the evil person from among you" (1 Cor. 5:13)."

He argued the Church has consistently modified its teaching "to agree with moral and social shifts in an unbelieving world" and would do the same on homosexuality. He accused Welby of abandoning the Bible in favour of a "discernment process" which "sets forth an evolving God, not the God of Scripture".

"It takes little reading between the lines of the Archbishop's speech to see the defenders of Scripture and orthodoxy being subtly impugned as 'power-hungry' elements in the church, hiding their true motives by "masquerading as a desire for order."

"The truth, however, is that Welby's doctrine of order and freedom, used as it is to justify a 'diversity' in the church leadership that tolerates and promotes homosexual relations as well as a possible embrace of homosexual 'marriage,' is antinomian to the core, masquerading as grace and freedom."