Two more teachers at an all-boys Catholic grammar school where its former deputy head sexually abused 10 schoolboys would "likely" have faced similar charges if they were still alive, police have said.
The revelation emerged after the Rev Alan Morris, 64, a church deacon, was jailed for nine years after he used a "cloak of discipline" to gain perverse gratification when administering corporal punishment at St Ambrose RC College in Hale Barns, Manchester, between 1973 and 1990.
An initial complaint to the police about Morris in November 2010 led to a large number of boys saying they too had suffered at his hand, while sex abuse allegations were also made against two other teachers at the school.
Other former students complained about "inappropriate use" of corporal punishment against a number of other teachers, many of who have also since died.
Ten former pupils claimed they were sexually assaulted by a Christian Brother whose holy order had run the school, while four ex-students said they were also sexually assaulted by a second teacher.
In a statement, Greater Manchester Police said: "Detectives established that both teachers were dead and had they not been would likely have been charged with serious sexual offences.
"A number of other pupils made reports to police about the inappropriate use of corporal punishment.
"Again, it was established that many of the teachers named were dead."
They added they believed there were other victims of Morris yet to come forward and appealed for them to do so.
The present governors of St Ambrose College expressed their "sincere regret" for any harm suffered but said the incidents involving Morris happened "many many years ago" and contemporary child safety policies were now in place.
Morris was said to have had a "fearsome reputation" as a strict disciplinarian and used his position of power to prey on students who were vulnerable and he knew would not report him to parents or the authorities, the court heard.
Morris was arrested on suspicion of indecent assault at his home in Rivington Road, Hale, in November 2012 following a complaint to the police.
Publicity about the investigation led to many more ex-pupils coming forward and saying they were sexually abused by him in the guise of corporal punishment, with many saying they were fondled as the discipline took place.
Morris denied all the charges and continues to maintain his innocence.
It emerged in court that Morris was first arrested by Greater Manchester Police in 2001 when one of his victims first made a historic allegation against him.
Morris would grab his arms from behind in class and then rock backwards and forwards making contact with his groin area, he said.
When interviewed, Morris denied any wrongdoing, describing himself as a "benevolent autocrat" and said his accuser was "a very good actor".
He told police he was homosexual but was only attracted to older men and could not pursue them in any event because of his vow of celibacy.
Morris was released without charge because of insufficient evidence and returned to his duties as deacon at the Church of the Holy Angels in Hale Barns, following his ordination in 1992.
He had already retired from teaching at St Ambrose in November 1995 when he suffered a nervous breakdown, the court was told.
Morris was convicted earlier this summer of 19 offences of indecent assault and inciting a child to perform an act of gross indecency.
At a second trial this month he was cleared of similar alleged historic offences at St Ambrose relating to two boys, while the jury could not reach verdicts on eight others.
The Crown decided today not to proceed with a retrial and reporting restrictions were lifted.
Opening her case in both trials, prosecutor Charlotte Crangle said: "This case involves what the prosecution say is a sustained campaign of abuse over a number of years against a large number of schoolboys under the care of the defendant in his role as a teacher and therefore protector of their interests.
"The abuse took place between the early 1970s and the early 1990s and was characterised by the defendant physically chastising various pupils at the school, and using that contact with them to further his own sexual desires.
"The prosecution say that the chastisement was perhaps in some cases deserved but it was conducted in an inappropriate manner and used as a cloak for a more sinister motive, namely the deriving of sexual pleasure through such contact with the boys."
Miss Crangle said an "atmosphere of sometimes brutal punishment pervaded" in the 1970s, in particular at St Ambrose.
All manner of implements were used by teachers to administer physical punishment but one of Morris's favourites was a makeshift paddle he named "the Paddywhacker", which he referred as his "friend".
Morris was said to have seen himself as "the chief policeman" at the school and sought out misbehaving pupils at break times as he roamed the corridors.
Morris denied any inappropriate activity with any pupil when he was interviewed following his arrest in 2012.
Various computer pen drives, DVDs and CDs were seized from his home.
Morris had a stash of gay porn, with some films depicting teacher and pupil discipline scenarios.
Internet searches on spanking and discipline of pupils were also found on his computer but Morris told detectives they were not something he had a particular interest in.
Morris sat with his eyes closed throughout the sentencing with his walking cane propped up to his face.
Sentencing him, Judge Timothy Mort said Morris had escaped justice for so long because he had ruled with fear as he handed out the punishments, with many of the boys believing they had done something wrong - whether that was the case or not - and subsequently did not tell their parents.
He added: "Many families who were devout Catholics felt the teachers could do no wrong.
"It is also clear that you calculated by becoming head of discipline you had the respect of the head (teacher) and with disdain for the governors you were really confident you could act above the law.
"It is clear that they (the victims) were telling the truth and it is an interesting observation that during this trial I had cause to mildly rebuke one of them who went up to you and said 'Remember the school motto' which loosely translates as 'Dedicate your life to the truth'.
"It seems at least the pupils were loyal to the motto of their old school."
Molly Whittall, from lawyers Slater & Gordon who are representing some of the victims, said: "The reaction to the verdicts and sentencing by the clients I have been able to speak to ranges from relief that Morris has been brought to justice for the majority of the offences he faced, through to a feeling that institutionalised abuse in schools, particularly those run by the Catholic Church, has still not been fully addressed and admitted by the church.
"From a legal viewpoint. the guilty verdicts prove that our clients were right and indeed courageous in coming forward.
"We are pursuing civil actions on their behalf and hope that the school will now settle these claims as quickly as possible to allow our clients to move on with the rest of their lives."