The Archbishop of Canterbury Justin Welby and Pope Francis gave their backing to a ground-breaking ecumenical initiative to combat modern slavery and human trafficking; a united agreement between Anglicans and Catholics.

The Global Freedom Network was created on 17 March to help eradicate a global injustice affecting up to 29 million people. The agreement was co-signed by the Archbishop of Canterbury's representative to the Holy See, Archbishop Sir David Moxon, the chancellor of the pontifical academies of science and social science, Bishop Sanchez Sorondo and Andrew Forrest, the founder of the large international anti-slavery organisation Walk Free based in Perth, Australia.

In a statement the Archbishop of Canterbury said: "We are now being called into a deeper unity on the side of the poor and in the cause of the justice and righteousness of God. For this reason, the new Global Freedom Network is being created to join the struggle against modern slavery and human trafficking from a faith base, so that we might witness to God's compassion and act for the benefit of those who are abducted, enslaved and abused in this terrible crime".

Although the transatlantic slave trade was banned in 1807 and slavery was abolished across the British Empire in 1834, it still exists today. Children are sold into slavery to pay family debts; people pay for passage, only to be trafficked over borders and find forced labour conditions.

It is estimated that between 12 and 27 million people worldwide are enslaved into forced labour and sexual exploitation. Each year, about 2 million people are victims of sex trafficking, 60 per cent of whom are girls. Human organ trafficking is rife: annually around 20,000 people are forced or deceived into giving up vital organs.

Victims are hidden away in both the world's richest and poorest nations – in brothels, illegal establishments, factories and private homes as well as on farms and fishing boats and in many other places.

Director of the Anglican Centre in Rome, Archbishop David Moxon, has been closely involved in the negotiations which have brought about this landmark in Church co-operation. He said: "Human slavery is a plague on a vast scale in many countries across the world today. This situation is not improving but is probably deteriorating.

"To quote Pope Francis: 'We must unite our efforts to free the victims and stop this increasingly aggressive crime which threatens not only individuals but the basic values of society.' Representatives from our churches have made an agreement to act together: one Church, one world – God's world – where everyone can walk free."

The Global Freedom Network is an open association and other faith leaders are invited to join and support this initiative. The joint statement reads: "The Global Freedom Network will take up the instruments of faith – prayer, fasting and almsgiving. There will be a world day of prayer for the victims and for their freedom. Dedicated prayer networks will be formed in all parts of the world".

Evangelical Christians have long been active in campaigning against slavery. Dr Dave Landrum, director of advocacy at the Evangelical Alliance, said: "Evangelical Christians have an illustrious history in the fight against slavery, and we are still fighting to end it today. Inspired by people like William Wilberforce, John Newton and countless others, we are committed to addressing this profound evil by educating and mobilising the Church to influence national and international policy.

"Alongside our public policy campaigns in the parliaments of Wales, Scotland and Northern Ireland, the Evangelical Alliance is presently working with a number of partner organisations to shape the Modern Slavery Bill in the UK parliament.

"I hope that the formation of the Global Freedom Network will enable a more concerted effort by the world's major faiths to end slavery."