In the Catholic Church the Seal of the Confession is the absolute duty of priests not to disclose information they learn from penitents.
The Church has traditionally taught that this is absolutely inviolable under all circumstances, and that breaking it for any reason is a grave sin punishable by excommunication.
Cardinal Nichols, who is President of the Catholic Bishops' Conference of England and Wales, told the IICSA yesterday that throughout history, priests have died to defend their role in confession, and that if this were to be challenged, “it might come to that” again.
Cardinal Nichols, said priests had been put to death in years gone by in their defence of the Seal of Confession and after refusing to divulge what a penitent had told them.
He told the Inquiry: “"I would defend the Seal of Confession absolutely. The history of the Catholic church has a number of people who've been put to death in defence of the Seal of Confession.
“It might come to that. But the Seal of Confession is of a sacred nature and its at the heart of the priest ministry acting in the name of the Father, and of the Son and of the Holy Spirit."
He added: “I think the Seal of Confession is an essential part of the exercise of priesthood as a nexus between my sinful humanity and the mercy of god, and I would defend the Seal of Confession absolutely."
Last year a string of child sex-abuse scandals in Australia prompted a five-year-long Australian judicial inquiry that documented widespread and historic abuse of children in the country’s Catholic institutions.
Following its publication, several Australian jurisdictions have passed laws that will soon require Catholic priests to break that seal.
Cardinal Nichols yesterday urged the government’s IICSA to think carefully before recommending that Mandatory Reporting be brought in for priests, as it could put them at risk of false claims that someone had confessed.
Brian Altman QC, counsel for the IICSA, asked if the inquiry were to recommend breaking the Seal of Confession, if it would be well received by the Bishops' Conference. Cardinal Nichols replied: "It would not be well received, it would be rejected.
"It would also put every priest in this country in a position of great liability because he would not be able to defend himself if someone went forward and said 'I told Father X that I am an abuser' - anybody could do that and no priest could defend himself."
Speaking to the inquiry board, he added: "Therefore I hope you consider very carefully this matter."
Cardinal Nichols said no-one had ever disclosed to him during a confession that they were a paedophile, nor had any victim mentioned it in the course of a confession.
His belief was that child abusers had convinced themselves they were not doing anything wrong, and were therefore "very unlikely to confess to it as a sin".
Earlier this week Cardinal Nichols had told the hearing that the Catholic community in the UK has been struggling to cope with “presence of evil embodied in its members” for decades.