Bless me Father, but can I trust you?, by Dark Box John Cornwell, Irish Independent (February 16, 2014)

Clerical sex abuse is modern Ireland's Famine. It's the event which has shaped and shaken the country more than any other. The who, what, when and where are slowly being excavated, but the why still remains unanswered. That's the task which the Cambridge academic and author John Cornwell sets himself in his new book.

He has a startling and original theory to put forward, which is that the rise in child abuse by priests throughout the Catholic world was linked directly to changes in the customs around first communion and confession which came into force under Pope Pius X in the early part of the last Century.

With Catholicism "seduced and corrupted on every side by secular influences", Pius was desperate to haul the faithful back into line. One weapon was a ruthless spy network which reported on priests with liberal views in an Inquisition-style "reign of moral terror".

The other was a hardening of the rules around communion – which he now demanded be taken more regularly, ideally every day– and the declining practice of confession, which suddenly went from an annual to a weekly obligation.

The most radical change, introduced by Papal decree in 1910, was that confession was now required of children, not after puberty as before, but from around the age of seven. This put predatory priests in a position where they had easy access to children.

Confession always had an erotic undertone. Two people, alone in a small, intimate space, sharing secrets. Now children were lured into that world, where damaged priests' neuroses, "symptomatic of their own adult sexual and moral anxieties", could be projected onto youngsters who were, in turn, taught to loathe themselves and their bodies and to fear God's wrath.

Cornwell has written extensively on church history, including Hitler's Pope, a classic biography of Pius XII; but he approaches this subject from personal experience too. As a boy in the 1950s in a junior seminary, he knew a priest who seemed to have a special affinity with the pupils. He was charming; up to date with the latest books and films; not at all like the "cold and austere" older clergy; and "confessions, held in his private quarters, became a treat and a privilege".

It was during Cornwell's first visit here that the man gave him a glass of Madeira and asked to examine his penis to see if he had any of the "well known deformities that led to excessive erections".

Having been abused five years earlier by a man making similar entreaties, Cornwell recognised what was happening and left the room. He still didn't report it, partly because he believed the seal of confession applied to him as well as the priest, and the following year the man in question, named in the book, was appointed chaplain of a boys' boarding school.

This pattern is one which Cornwell identifies repeatedly in his research. He quotes one priest who says: "In all those cases, the sacrament of confession was used (by the molester) to discover vulnerability and groom candidates for abuse."

Once an abusive priest was in such a relationship of trust with a child, the abuse could also continue elsewhere, whilst still tied, symbolically and psychologically, to the confessional. "The child's unquestioning trust continues to govern the relationship on trips, retreats, country walks, social occasions, sporting activities, hikes and journeys alone or in groups by car."

Cornwell cites scores of cases from the Irish church where children were abused after being targeted in confession.

Penitents were urged to tell only their own sins and this meant that they rarely reported the abuse to other priests in confession, though he cites one example of a boy who did and was then abused further by the new priest.

Cornwell casts his net wide, writing about the cultural portrayal of the Catholic Church in film and literature, and the psychological role which confession plays in human life, right up to the present day chat-show culture.

He unpicks, too, how thinking in the early part of the 20th Century was profoundly influenced by the creepy Freudian obsession with masturbation and child sexuality, and shows the way in which pop culture broke down the boundaries between generations and created further opportunities for abusers to access children.

But it's the way he maps the evil effect this confluence of forces had on vulnerable children which makes The Dark Box so compelling. It's a powerful and disturbing addition to the literature on the subject, and lays bare the dysfunctional nature of a church which has still come nowhere near to facing its own self-inflicted demons.