In a Vatican document in 2011 Pope Benedict XVI urged penitents to rediscover the sacrament of confession. “It is necessary to return to the confessional as a place in which to celebrate the Sacrament of Reconciliation, but also as a place in which ‘to dwell’ more often,” he wrote.

He could have added that there was no need to worry about a queue, because, based on John Cornwell’s insightful and rigorously researched book, we can conclude that penitents sent a telepathic reply along the lines of “Good luck with that one” and instead logged on to reddit.com and online poker. Some less technologically inclined penitents possibly hit the allotment or the bingo hall in Cabra. What they did not do in any great numbers is flock back to the confession box, which was likely being used to store cleaning buckets and an overflow of hymn books.

The Dark Box: A Secret History of Confession reveals the "massive collapse" in Catholics attending confession. Cornwell tells us that confession is "so poorly attended in recent years that in many parishes the sacrament is only available by appointment". Curiously, despite adults turning their backs on it, it is still maintained as a tradition, albeit in an evolved "reconciliation" form, that seven-year-old children endure.

Cornwell argues quite effectively that this outright rejection of confession “is a crucial symptom of a wider crisis within the Catholic Church”. This isn’t an altogether startling revelation, as the wider crisis just seems to widen revelation by revelation, but what Cornwell’s book collates for the reader is a multicentury historical context of how this gulf between Catholics and this specific sacrament of their faith evolved. They have not necessarily abandoned other aspects of the faith to this extent.

The Dark Box details the maze of directives around confession, by sometimes slightly barmy-sounding theological characters, who underestimated the deviant holy man's ability to manufacture opportunities for depraved acts, while using the channel of confession both as a grooming post and a spot to obtain absolution from those abusive acts.

I highly recommend a stable position, with back support, when reading this book, as your stomach will churn as you read of the miserable, twisted layers of abuse, fear, shame and sexual exploitation inflicted on innocent children, who through the confession box became easy targets for paedophiles.

Devout adults likewise had their trust abused by a church that sought only to control and regulate its congregation, rather than understand or protect them from the aberrant urges of some of its own. All was carried out under the guise of the liturgy, the word of God, the need to absolve for sin, and avoid purgatory in the next life.

In these moments of abject and unremitting failure the church merely offered a live preview of purgatory and, sadly, committed an untold amount of “soul murder”.

Cornwell, author of Hitler's Pope and 20 other books, is a great guide to these disturbing waters. A former seminarian, he injects his personal history into the book in places, but it never overwhelms the wider text. Less proves more. When writing on a topic this emotive, it's even more crucial to let the reader marinate into the material to understand the implications of it.

It wasn’t until the 13th century that Rome, under Pope Innocent III, made it obligatory for every Catholic to take confession annually or risk losing much, including burial rights. Innocent was endeavouring to heave out heretics through his “tribunals of inquisition”. He nixed the Magna Carta and recentralised power to Rome away from the bishops, preferring them to properly train confessors in more rigorous extraction techniques.

Confessors were encouraged to interrogate penitents about their sins and not merely leave confession to the volunteering of information. This interrogation of penitents would later ricochet because it led some to take advantage of penitents, once weakness was exposed, and facilitated confessors to invert information and resort to flagrant sexual badgering. Another problem with the forensic probing of sin was that it could tempt penitents to commit sins they had never previously heard of.

We need to back up a few centuries also and enter the maze of decrees to understand how we ever ended up inside the box. We owe the physical confessional to Cardinal Charles Borromeo, in 1576. Borromeo became an abbot at the age of 12, aided by the fact that his uncle was Pope Pius IV. He invented the wooden confessional box to thwart physical contact between the confessor and the penitent.

We owe the practice of seven-year-olds making confession collectively to Pius X, who took office in 1903; he sliced the age at which children would commence confession and communion. Pope Pius X was an anti-intellectual, robust restorer of Christ and martinet for the vocation of priesthood. He was a practical, anti-pomp pope, who demanded near military discipline and deference to superiors from priests and penitents alike. He banned newspapers and radio in seminaries, restricted access to secular education for seminarians and cut out community engagement.

His approach emulated the earlier example of a bizarre French country priest, Jean-Marie Vianney. Vianney practised a rare form of self-flagellation to clear his parish of the devil. This included spending chunks of the night sleeping prone on a cold floor, whipping himself until his blood decorated the walls and living off a single pan of potatoes per week. He closed pubs, banned dancing and turned the village into a “spiritual concentration camp” whereby he’d hear confession 14 hours a day and, unsurprisingly, weep inconsolably in the process.

Much later, after Pius X, came birth control, which evidently drove a wedge between the faithful and confession. When we consider the breadth of the history of confession, it resembles a series of complex clumps floating, submerging and reconstituting down a river of centuries. To understand its current or evolving state it’s certainly worth boarding Cornwell’s raft.

The Vatican has attempted to reinvent confession during the past 40 years, and it is now framed less in terms of sin and more in terms of “reconciliation”. But it could be a long time before spiritual consolation comes to the minds of those psychologically scarred by its earlier iteration.

This review was edited on March 24th, 2014