The Archbishop of Wales, Dr Barry Morgan, welcomed the move and said: "This film will not be easy watching for church members as it reminds us how people among us have been ostracised and mistreated because of their sexuality.

"By sharing the personal stories of those who have suffered and been hurt I hope this powerful film will bring home to all the scale of the damage done and ultimately help change attitudes within the church."

But Dr William Strange, vice-chair of the Evangelical Fellowship in the Church in Wales, told Christian Today it was "regrettable" the Church had made this "public demonstration after our governing body decided not to give the green light to change teaching on sexuality".

The local Bishop of St Asaph, Gregory Cameron, will take part in a panel discussion after the event on Tuesday.

Mike Jones from the campaign group Changing Attitude, Trawsnewid Agwedd Cymru said: "We are very grateful to the Iris Prize Outreach team, and the Big Lottery Fund Wales, for making it possible for us to produce our film, 'All One in Christ' and for the Church in Wales bishops who encouraged us to do it.

"Those who took part in the film describe the pain experienced by LGBTQIA (lesbian, gay, bisexual, trans, queer, intersex, asexual) people, as a result of being made unwelcome, or the fear of being unwelcome, even rejected, by the Church. But the film is also full of faith, and hope, and even love, for a Church that continues to struggle with accepting people whatever their sexuality.

"We are all one in Christ. This means, for example, that everyone should be able to celebrate their marriages or civil partnerships in churches and receive God's blessing, wherever they live in Wales. Many -- and, in some parts of Wales, the majority -- of church members, clergy and bishops agree. But not all do.

"Our hope is that the film will challenge and inspire the Church in Wales to fully include LGBTQIA people in its life and ministry, and be a sign of God's love and justice in a broken world."