Pope Benedict XVI has instructed Roman Catholics to pray “in perpetuity” to cleanse the church of paedophile clergy.

All dioceses, parishes, monasteries, convents and seminaries will be expected to organise continuous daily prayers to express penitence and to purify the clergy The Times has reported.

Vatican officials said every day each parish or institution should designate a person or group to pray that the church rids itself of the scandal of sexual abuse by clergy.

Alternatively, churches within the same diocese could share the duty. Prayer would take place in one parish for 24 hours, then move to another parish.

Vatican-watchers said there was no known precedent for global prayer on a specific issue of this kind.

Officials said the prayers were in addition to support for legal action against paedophile priests by their victims and a code adopted two years ago by the Vatican to try to ensure that men “with deep-seated homosexual tendencies” do not enter seminaries to train for the priesthood.

The instruction was sent to bishops by Cardinal Claudio Hummes of Brazil, head of the Vatican Congregation for the Clergy. He told L’Osservatore Romano, the Vatican newspaper, that he was acting in the Pope’s name.

The Pope wanted Catholics to pray for the “mercy of God for the victims of the grave situations caused by the moral and sexual conduct of a very small part of the clergy,” he said.

Cardinal Hummes said the aim was to put a definitive stop to a scandal that had damaged the image of the church and forced archdioceses in the US, including Boston and Los Angeles, to pay millions of dollars in compensation to the victims of abuse.

He said the paedophile scandal was exceptionally serious, even though it was probably caused by `”no more than 1 per cent” of the 400,000 Catholic priests around the world.

When the paedophile scandal erupted in Boston five years ago, Pope Benedict, or cardinal Ratzinger as he was then, accused the media of exaggerating the crisis. He later took a tougher stand and was said to have been behind the statement in 2003 by Pope John Paul II to a meeting of US churchmen in Rome in which he said: “The abuse which has caused this crisis is rightly considered a crime by society and is also an appalling sin in the eyes of God. People need to know that there is no place in the priesthood and religious life for those who would harm the young.”

In 2005 Pope Benedict lifted the legal protection the Vatican had given to Father Marcial Maciel, the Mexican founder of the Legionaries of Christ who was accused of sexual abuse of youngsters. Maciel was banned from saying Mass or speaking in public.