More than 100 Anglicans including the Dean of St Paul's have written a letter to the Archbishops of Canterbury and York, urging repentance for "second class citizens" treatment of gay people. The letter is timed to coincide with the meeting of leaders of the 38 provinces of the Anglican Communion which begins tomorrow in Canterbury.

The meeting was called by the Archbishop of Canterbury Justin Welby in an attempt to avoid a damaging schism over sexuality. Some conservative Primates are threatening to walk out if liberal provinces such as The Episcopal Church of the US are not disciplined for ordaining openly gay bishops.

In the letter, senior church figures including cathedral deans, retired bishops and well-known lay figures call on the Church to acknowledge its failure to care for lesbian, gay, transsexual and bisexual Christians around the world.

They plead for the primates to act in Christ-like love "towards those who have been ignored and vilified for too long." The leaders say: "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."

They continue: "We, the Church, need to apologise for our part in perpetuating rather than challenging ill-informed beliefs about LGBTI people, such as the slanderous view that homosexuals have a predisposition to prey on the young."

The signatories include eight retired bishops and a serving bishop, Bishop of Buckingham Alan Wilson. 

In an exclusive article for Christian Today, the Dean of St Paul's, the Very Rev David Ison says he hopes the Primates will find a a way to stay together but fears they will give up and walk away from each other. He compares the battle to fights over immigration, and the turmoil in the Middle East wreaked by Islamic State. He writes: "The sexuality divide focuses the big question facing the whole of humanity, which underlies other huge topics the Primates are dealing with (whether religious persecution, the safeguarding of the vulnerable, people trafficking, the treatment of refugees). How do we treat people who are different from us? The forces of Daesh in Syria seek to eradicate difference and make everyone else like them, through violence and the threat of death; extremist political parties see immigrants as a threat; leaders make themselves lifelong rulers by destroying those opposed to their control of power."

He adds: "Will the threatened splits and walk-outs happen – or can the Primates model something different? Does the truth belong to one side, are there two incompatible truths – or are we servants of one God with something to learn from each other in order to become the one Body of Christ in love?"

Prominent gay Christian Vicky Beeching, who came out in 2014, said: "Social and religious attitudes are shifting among young people. Many cannot morally align themselves with a Church that perpetuates LGBT discrimination. If we want to ensure the future life of our Church this issue needs urgent attention and great pastoral sensitivity. To see the Church repent of damaging attitudes would help many young people feel a reconnection with it."

The letter has been coordinated by Jayne Ozanne, a member of the General Synod who is standing for election to the Archbishops' Council and who came out last year in an interview with Christian Today. She said: "The signatories come from across the full breadth of the Anglican traditions, and from right across the country. From the Dean of Truro to the Dean of Carlisle, and from the MP for Exeter to the Master of Trinity Hall at Cambridge University. It is so encouraging to see so many senior Anglicans now standing alongside their LGBTI brothers and sisters, recognising their woeful treatment by the Church to date."

She said the Church was increasingly perceived as irredeemably "anti-gay" by increasing numbers who don't understand why the church continues to discriminate, nor why it is allowed to do so. "Until we repent of our treatment of our LGBTI brothers and sisters, attempts by those within the worldwide Church to conduct meaningful conversations will risk appearing hollow and insincere."