Since public hearings at the Royal Commission into Institutional Child Sexual Abuse began 17 months ago Australia has become used to seeing a regular pattern to how it plays out:

A lone victim speaks out against an institution.

A cover-up is put in place to protect the institution's reputation at the expense of the victim.

Frustrated, crushed, shocked, betrayed, the victim seeks to be heard by bashing down a door - either through police, inquiry or media.

Only when another institution draws near is a public apology made.

For more than a year the nation has watched as some pillars of society, including the Catholic and  church, the Anglican churches, Jewish centres and schools in Sydney and Melbourne, the Salvation Army, the YMCA, and various state governments, have been exposed as providing opportunity and shelter to paedophiles.

The culture that permeated Knox revealed in the royal commission this week has shocked many out of their faith in the school's tradition and its promise to enable boys to succeed and grow into young men of faith, wisdom, integrity and compassion.

Sexuality is hard country for teenagers but many students at high net worth private schools live with a morbid fascination about it, their discomfort and longing to belong often expressed through showy displays of revulsion towards sexual ambiguity.

A throwaway insult for generations of Sydney private school boys runs:

"Tiddlywinks, young man

Run as fast as you can

If you can't get a girl

Get a Cranbrook man"

The rhyme was readily adapted to Grammar/Riverview/Barker.

For decades, Knox had been the target of gossip, lies and innuendo along the North Shore Line.

And then in 2009, something far more serious erupted from these nudge nudge, wink wink cultural undercurrents when numbers of former students alleged they had been sexually abused by teachers at the school between 1970 and 2009. It was the ultimate breach of the trust they and their families had placed in the school.

Police established Strike Force Arika to investigate the allegations. Five teachers were convicted of child sex offences against students. The royal commission was given evidence of abuse by another three. One, art teacher Bruce Barratt, died in the mid-1980s, and was remembered on a school gate with the droll epitaph, "He touched us all"." The plaque has been removed.

For more than three decades boys were subjected to the teachers' predations, the school failed to notify police of any incident of child sexual abuse.

Tim Hawkes, the headmaster of The King's School, Parramatta, was a former teacher and boarding house master at Knox when one of his young boarders was groped in the dormitory just before dawn in 1988 by a man wearing a balaclava and Knox tracksuit. Hawkes told the commission he did not call the police because he believed it the responsibility of the then headmaster, Ian Paterson. He said he was then unaware of the legislative requirement to report sex abuse to the Department of Family and Community Services.

"I think in those days, authority structures in schools - we're talking about over a quarter of a century [ago] - were very much more hierarchical than they are today. They are very much more horizontal today and, I think, thankfully so," he said.

"And I think today, not only aided and abetted by changes to the law but also by social custom, I think the empowerment of people at all levels and seniority within schools is such that, today, the initiative to notify police would be unquestioned."

Such buck passing outrages Lesley Saddington, whose son, Tony Carden, died of AIDS aged 33. She says he was nine at Knox preparatory school in 1971 when he was "groomed" by teachers. She believes the abuse continued at senior school.

"One can only arrive at the conclusion that over the past several decades Knox, as a school run by the Uniting Church, has lost its moral compass," she says.

There is no doubt that the five convicted Knox paedophiles, Craig Treloar, Damian Vance, Adrian Nisbett, Barrie Stewart, and Roger James, chose their targets with precision.

They picked the weak and vulnerable with boarders the easiest of prey. Day boys with troubled home lives were vulnerable to grooming.

Victims told the royal commission of feeling so ashamed they could not tell anyone, let alone complain to someone in authority.

A 52-year-old former boarder given the pseudonym ARY recalled Stewart's opportunistic groping in the school's hallways. "Often in passing in the hallways he would grab a boy's genitals," he said. "This happened so casually it was like a handshake."

Those who spoke up were shunned by peers. "They became victimised and ostracised in the boarding house," ARY said. "They were seen as weak and they became everybody's bitch."

Former student Scot Ashton could see no point reporting abuse, which included an incident where music teacher Stewart inserted a finger into his anus.

"I felt very isolated because I was the victim of abuse and had this terrible shame and secret which I could not discuss and I was intimidated by the general bullying culture of the school which preyed on the vulnerable and weak and I could not afford to be vulnerable by complaining about the abuse and I felt that it would be pointless," he told the commission.

And then there were constant reminders of how privileged they were to be at such a good school and who would want to bring that into disrepute?

"Everyone was expected to keep up the reputation of Knox," ARY said.

He told the commission he would find it "astounding" if staff weren't aware of the extent of the abuse, a sentiment echoed by many.

Coryn Tambling, who boarded during the 1980s, sheeted the blame home to then headmaster Paterson.

Tambling was 13 and a boarder from the Northern Territory when Treloar showed him hardcore pornography featuring bestiality and paedophila before propositioning him for sex. His behaviour deteriorated and his parents asked what was wrong.

"I said that 'one of the teachers in the boarding house had showed me pornography and asked me to suck his dick'," Tambling said. "My mother didn't believe me. She said, 'you would have told us in one of your letters home if it was true'. My mother had continued to hold a very high opinion of the school."

When his father said there wasn't much to worry about, "I went back to Knox, heartbroken and angry".

Other students, whose behaviour and academic performance plummeted in the wake of abuse, were simply asked to leave school.

A man given the pseudonym ARG, molested by art teacher Barratt and English teacher Nisbett, told of being forced out but being unable to tell his parents why.

"They were beautiful people and churchgoers," he said. "I was scared, embarrassed and didn't know whether anyone would believe me. I had horrible emotions going."

Meanwhile, the behaviour of the paedophile teachers continued largely unchecked.

The commission is yet to hear evidence of Stewart being sanctioned in any way. Treloar kept his job after admitting to watching pornography with boys. Vance was allowed to "resign" to spend time with his sick mother in 1989, despite the commission hearing the school was aware he had indecently assaulted a student underneath the Knox chapel.

Religious education teacher Christopher Fotis was never charged over sexual abuse at Knox but allowed to "resign" after being arrested for masturbating outside a school in North Ryde in 1989. Fotis failed to appear at the commission and an arrest warrant was issued on Wednesday.

Fotis and Vance were provided with glowing references about their professional skills by Paterson.

Treloar was still teaching at the school when arrested over multiple sex offences in 2009.

John Rentoul, a former assistant headmaster of Knox, told the commission that it was "extraordinary and reprehensible that these men continued to teach at Knox and abuse students.".

"I believe the school was more interested in protecting the reputation of Knox than ensuring the safety and welfare of its students," he told the commission.

In heartbreaking testimony, Rentoul told the commission his son, David, was abused by Stewart, something he believes led to David's early death from multiple organ failure.

The 80-year-old, who left Knox in 1981 to teach in New Zealand, told the commission that private school students may be more vulnerable to abuse by teachers.

"In my view, private schools may be more susceptible to instances of sexual abuse because of more opportunities for the development of close relationships between teacher and students."

Speaking outside the commission, Independent Education Union general secretary John Quessy agreed this was an issue for independent schools.

"Where you have situations where students and teachers are interacting extensively outside of a classroom situation it would appear there are more opportunities for impropriety to take place," he said.

Some former students have received six-figure compensation payments from the school and the Uniting Church but say the money will never fix the damage done.

For others, the legal process was unnecessarily gruelling.

"It made me feel like I was being screwed all over again," former student Adrian Steer drily observed of his experience with Knox's lawyers.

Counsel assisting David Lloyd lamented lack of documentary evidence about the abuse which complicated the redress process.

"A difficulty has arisen in investigating these questions because of the paucity of contemporaneous documentary records which record allegations of abuse and the school's response to them," he said.

The commission has been told that Paterson kept all documents regarding allegations of abuse in a black folder in his office.

When new headmaster Peter Crawley took over from Paterson in 1999 he was told the folder contained the sensitive information but was stunned to see just a few snippets of notes and nothing of substance.

"In my view it was a very unprofessional folder," he said. "I remember just being aghast at what I was looking at."

Former head of the Knox Grammar Preparatory School Robert Thomas was similarly surprised when he looked at Treloar's file and saw no mention of his six-month suspension for watching pornography with students.

The commission heard that files of students who made complaints have also gone missing,

Lloyd said the hearing would examine the fate of these missing documents, "whether they were deliberately destroyed in order to eliminate evidence which might adversely affect the school, and who from the school might have been involved in and/or aware of any deliberate destruction of relevant documentary records"."

This culture of cover-up only adds to the trauma of those who have suffered abuse, according to Craig Hughes-Cashmore, co-founder and director of Survivors and Mates Support Network

"Sadly, many feel that they won't be believed and even if they do speak up, there is that constant fear that it will just be swept under the rug," he said.

Adults Surviving Child Abuse: 1300 657 380

Survivors and Mates Support Network: 02 8355 3711

Bravehearts: 1800 272 831