You didn’t spend long in evangelical circles of the Church of England during the late 1970s without bumping into an outwardly charming young man named John Smyth.

A famous barrister, who’d acted for morality campaigner Mary Whitehouse in blasphemy and pornography cases against Gay News, Channel 4 and the National Theatre, Smyth also chaired the Iwerne Trust, a charity which ran Christian summer camps in Dorset each year.

His annual retreats, at which largely well-bred young men swam, played sports, and attended Bible study classes, were designed to attract ‘future leaders’ who might go on to greater things.

They ranged from the Reform Party leader Richard Tice to the Right Rev Andrew Watson, who later became Bishop of Guildford. Today’s Archbishop of Canterbury, Justin Welby, volunteered as a dormitory officer for several years, while the broadcaster Anne Atkins spent the summer before she went up to Oxford as one of a handful of female volunteers, who were allowed on-site to peel spuds in the kitchens.

Smyth, who was married with two children, seemed ‘handsome, brilliant, charismatic’, Atkins later recalled, dubbing him ‘a Christian role model for many’.

Yet as scores of teenage boys who crossed the eminent QC’s path later discovered, there was a dark side to his beguiling personality. For Smyth would turn out to be a prolific child abuser, who used the Iwerne Trust’s seaside camps to target potential victims.

He had a particular penchant for pupils from Winchester College, the famous public school (and alma mater of Rishi Sunak) near his idyllic family home in Hampshire.

Young members of the school’s Christian Forum, which sent a delegation to the camps, would be invited over for Sunday lunch and a swim in the pool, before being lured into Smyth’s shed, where they would be instructed to confess various sins.He would then instruct them to strip naked, before undoing his trousers and using a garden cane to inflict brutal punishment beatings.

‘He made me strip off my clothes and he got out a cane and started to beat me,’ recalled Mark Stibbe, who went on to become an Anglican vicar.

‘He said, “This is the discipline that God likes, it’s what’s going to help you become holy”.’

Another victim, Richard Gittins, was beaten so hard he needed to wear a nappy to cover his wounds: ‘He said it wasn’t enough to repent your sins; that they needed to be purged by beatings. I had to bleed for Jesus.’

A third later told reporters: ‘After ten strokes, I felt my skin burn. After 20, I felt blood trickling down from my buttocks to my legs. At 30, he stopped and embraced me from behind, leaning against my back, nuzzling his face against my neck and whispering how proud he was of me.’

Not every boy who attended Iwerne camps ended up being beaten (there is, it should be stressed, no evidence that he targeted Mr Tice). But Smyth had abused roughly 30 boys before rumours of his revolting abuse reached the authorities.

In 1982, the Trust was informed that a 21-year-old student at Cambridge University had attempted suicide after being contacted by the QC and ordered to visit Winchester to submit himself to one of his sadistic attacks.

The charity instructed a vicar named Mark Ruston to investigate the student’s complaint. His written report, submitted later that year, found that at least 13 young men had been violently assaulted by Smyth. Smyth had ‘conned men into accepting’ the ‘horrific’ beatings after confessing to a variety of sins. They would be given 100 strokes of the cane as a punishment for masturbation and 400 for exhibiting the sin of pride.

Five of the 13 victims who spoke with Ruston (a friend, incidentally, of Mr Welby) said they had received 12 beatings and about 650 strokes over a three-year period. The other eight said they had each been hit about 14,000 times over a period of years.

One boy told him: ‘I could feel the blood spattering on my legs.’ Another claimed: ‘I was bleeding for three-and-a-half weeks.’

‘The scale and severity of the practice was horrific. I have seen bruised and scored buttocks, some two-and-a-half months after the beating,’ concluded the vicar, stressing that the assaults were ‘technically all criminal offences.’

Ruston’s report appears to have been shared with both the charity and Winchester College. But neither institution passed its findings to the police. Instead, they arranged for Smyth and his family to move to Zimbabwe, where he was allowed to start a new life far away from the boys he’d abused.

On paper, Smyth had supposedly agreed that he’d never work with children again. But in practice by 1984 he’d set up an organisation called Zambezi ministries, which recruited boys from the country’s leading schools to take part in holidays that were almost identical to Iwerne camps.

Among those believed to have made small donations to the organisation was his old chum Welby, who has said he was unaware of the reasons for his departure from the UK. The pair continued to exchange Christmas cards for several years.

In 1992 the body of a 16-year-old boy named Guide Nyachuru was discovered at the bottom of the camp’s swimming pool. A police investigation unearthed hair-raising allegations involving staff at the camps showering with boys and taking them on naked swims, while Smyth confessed to occasionally beating them across bare buttocks with either a table tennis bat or an implement called a jokari.

‘Experience has shown that with so many high-spirited boys we need some form of sanction,’ he claimed.

The authorities took a different view, and after a four-year police investigation into the death he was charged in 1996 with culpable homicide and injuring the dignity of five other boys who said they had been subjected to savage beatings. However the case was eventually dropped, after Smyth convinced Zimbabwe’s Supreme Court that prosecutors had failed to follow proper procedures, and he moved to Cape Town.

There, the prolific abuser once more set himself up at the helm of an organisation that provided counselling to young Christian men.

‘His practice of meeting young men at a well-known Cape Town sports club began with a game of squash,’ a local newspaper later reported.

‘It was followed by a shower in a common shower, then lunch over which we were told John would make generally unsolicited enquiries about the young men’s experience of pornography, masturbation and other sexual matters.’

The wheels only started to come off in 2012, when a victim named Graham (his surname was withheld) contacted the Church of England seeking counselling and an assurance that Smyth was not committing similar abuses in South Africa. For reasons now at the centre of controversy, Lambeth Palace, run by Welby from 2013, kept details of his complaint from the public domain.

Last week’s independent review by Keith Makin into the Church’s handling of the Smyth case makes clear that Welby became aware of the abuse allegations in August 2013. Yet details weren’t reported until February 2017, when Channel 4 news revealed that it had interviewed 22 of Smyth’s victims.

Even then, Smyth managed to escape justice. Doorstepped by broadcaster Cathy Newman, while visiting a friend in Bristol at Christmas, he said ‘I’m not talking about that’ when asked about his abuse. Followed down the street, with wife Anne by his side, Smyth continued angrily: ‘I’m not answering any questions.’

The prolific child abuser then returned to Cape Town, frustrating the police’s belated efforts to interview him, and died from a heart attack in August 2018, at the age of 77, taking what remained of his dark secrets to his grave.