The Bishop of Dromore, John McAreavey, who announced his resignation earlier this week amid controversies over his handling of a paedophile priest, has told his diocese that he wrestled with the decision for a number of weeks.

A fortnight ago last Tuesday, BBC Northern Ireland's 'Spotlight' programme broadcast interviews with a number of men who survived child sexual abuse at the hands of the late Fr Malachy Finegan, a senior cleric in the diocese.

They criticised Bishop McAreavey for concelebrating mass with Finegan in the year 2000 despite the fact that, years earlier, McAreavey's predecessor had banned the paedophile from public ministry because of his crimes.

The victims also said also they had been deeply hurt by the bishop's decision to celebrate the paedophile's funeral Mass in 2002, an action the bishop described as 'wrong' following the 'Spotlight' broadcast.

In 1994, the then Father McAreavey, a senior canon - or church - lawyer, was first officially made aware of one of Finegan's victims, abused while attending St Colman's Grammar School in Newry, County Down, where Finegan worked and where he served an eleven-year stint as President.

A source close to Bishop McAreavy has told RTÉ News that his predecessor, the late Bishop Francis Brooks, failed to tell him about a second victim of Finegan's after Dr McAreavey was appointed to lead the diocese in 1999.

In all, 13 complainants have come forward and the diocese has made settlements with many of them.

The same source has said that the outgoing bishop had no option but to allow Finegan remain on the altar at the mass in 2000.

He said Dr McAreavey had arrived at the church in Hilltown, County Down to find Finegan dressed in celebrant's robes as the Mass to mark the parish's 150th anniversary was about to begin.

"He decided that, rather than make a scene by throwing him off the altar, he'd reprimand him a two days later," the source said, adding that the bishop formed the impression that Finegan was very confused about dates of alleged offences at the face-to-face interview.

Within weeks, the source says, Finegan was being treated for advanced dementia.

This evening's letter to the people, members of religious communities and the clergy of the diocese has been published to coincide with the beginning of Saturday Vigil Masses.

In it, Dr McAreavey says that earlier today he wrote his letter of resignation to Pope Francis.

"I do so with a heavy heart," he continues. "I wrestled with this decision over recent weeks; it was not an easy decision to take. Following recent media coverage which has disturbed and upset many people, I decided on Thursday to resign."

Pope Francis is not obliged to accept such resignations. His predecessor, Pope Benedict XVI, rejected the resignations tendered in 2009 by Dublin's two Auxiliary Bishops, Éamon Walsh and Raymond Field who protested that they had been unfairly criticised following the publication of the Murphy Commission report on cover-ups of clerical child sexual abuse in the Dublin Archdiocese.

He continues: "I would ask you first and foremost to continue to hold in your prayers those who have been abused and all who are suffering at this time.

"Until new arrangements for the leadership of the Diocese are in place, Canon Liam Stevenson, the Vicar General will take responsibility for the day-to-day administration of the Diocese. As regards the celebration of Confirmation, the priests of each parish have been delegated to minister this Sacrament."

In recent weeks, a number of parents have warned the bishop that they would not allow their children to be confirmed by him over the coming weeks because of his handling of Finegan and of complaints against the paedophile.

Bishop McAreavey concludes what appears to be his valedictory letter with the words: "To serve as Bishop of Dromore, my home Diocese, has been the greatest privilege of my life, though not without its challenges.

Finally, I want to say thank you for your kindness and co-operation over my time as Bishop. Please keep me in your prayers, as I will keep you in mine."

Yesterday, Amnesty International in Northern Ireland and a lawyer representing some survivors of Finegan's abuse called on the British government to establish a public sworn inquiry of into the responses to clerical sexual abuse north of the border.

Amnesty's Jim Corrigan said the McAreavey controversy was not an isolated one and cited similar allegations of cover-ups by the retired Primate of All Ireland, Cardinal Seán Brady, the former Bishop of Derry Séamus Hegarty,who subsequently ran the neighbouring diocese of Raphoe, and the late Bishop of Derry Edward Daly.