The French Bishops have pledged zero tolerance for paedophiles. At a meeting in Lourdes on Thursday they said in an official statement: 'When the aggressor is a priest it is a double betrayal. The bishop's responsibility in this domain is clear but it is also delicate. He cannot stand back passively, and even less so cover for criminal acts." 'But paedophilia is still a poorly understood phenomenon -- it hides, it is rarely admitted and it is often difficult for a bishop to gather enough hard evidence to establish whether a priest has indeed carried out acts of a paedophile nature.' Last month a French priest was sentenced to 18 years in jail for repeatedly raping one boy and abusing several others over a period of more than a decade. Magistrates are also investigating allegations that a bishop failed to bring the case to light despite being made aware of the priest's activity. Spokesman Mgr Michel Dubost said that future priests should be given better counselling and that they were often ill-prepared for the hardship of clerical life. Speaking to the religious affairs magazine La Vie, he said: "We've left priests living in misery and isolation, while asking them to do just about everything without any consideration for them. It seems inevitable some of them crack up."