Bishop Gianfranco Girotti, head of the Apostolic Penitentiary, the Vatican body which oversees confessions and plenary indulgences, said after a week-long Lenten seminar for priests that surveys showed 60 per cent of Catholics in Italy no longer went to confession.

He said that priests must take account of “new sins which have appeared on the horizon of humanity as a corollary of the unstoppable process of globalisation”. Whereas sin in the past was thought of as being an invididual matter, it now had “social resonance”.

“You offend God not only by stealing, blaspheming or coveting your neighbour’s wife, but also by ruining the environment, carrying out morally debatable scientific experiments, or allowing genetic manipulations which alter DNA or compromise embryos,” he said.

Bishop Girotti said that mortal sins also included taking or dealing in drugs, and social injustice which caused poverty or “the excessive accumulation of wealth by a few”.

He said that two mortal sins which continued to preoccupy the Vatican were abortion, which offended “the dignity and rights of women”, and paedophilia, which had even infected the clergy itself and so had exposed the “human and institutional fragility of the Church”.

The mass media had “blown up” the issue “to discredit the Church”, but the Church itself was taking steps to deal with it.