A young boy whose private parts were repeatedly sexually fondled by his chemistry teacher needed two bladder operations later in life because of the abuse.
Dad-of-three Michael Wilde molested the pupil on three separate occasions during the 1970s when he taught at Wade Deacon High School in Widnes.
One happened in the science laboratory when the now-70-year-old approached him from behind, and squeezed his private parts over his trousers.
Wilde then "walked away as if nothing had happened," Liverpool Crown Court heard, leaving the victim in "disbelief."
In another incident, the boy had inhaled gas during an experiment when Wilde saw the opportunity to take advantage of him.
The Warrington man moved the child into a back room and unzipped his trousers before sliding his hand into his underpants, groping his testicles.
The final attack happened when the pupil was 12, in the Wade Deacon gym, as Wilde grabbed the youngster's waist, pushed the youngster onto a bar and then slid his fingers onto the victim's testicles.
Today, Wilde was jailed for a fourth time, all in connection with his spree of offending during the early to mid 1970s.
Since the first batch of abuse was reported in the media, more victims have come forward, with a total of seven boys, now adults, complaining to police.
The latest victim, who only discovered Wilde's abuse of other boys when a taxi driver mentioned it as they drove past the Widnes school, kept his secret for decades before disclosing it to his brother and wife.
In a Victim Impact Statement, the man, who cannot be named, described how the abuse had particularly impacted on his bladder, leaving him with problems urinating and with it feeling "uptight."
He continues to work "in close proximity to a toilet," and particularity struggles with "bullying" men in positions of authority.
The victim said the abuse left him with low self-esteem, loneliness, sleep difficulties, stomach aches and nightmares of "someone being in the room, ready to pounce."
Wilde admitted three new counts of indecent assault on a young boy, and was jailed for 12 months.
Cheryl Mottram, prosecuting, also outlined details of Wilde's past three criminal cases, all involving abuse at Wade Deacon.
One victim, who reported the matter to police in 2014, recalled the chemistry teacher controlling the pupils and hitting them with the tube of a Bunsen burner "for pleasure."
Wilde, who also took part in PE lessons, had a habit of sitting in the shower room as they were naked, washing themselves.
Once, during a circuit training session, he held aloft a boy on a beam, putting his hand up his shorts, and fondled his private parts for one minute.
Two weeks later, it happened again, it was heard.
A second victim, who started the secondary school in 1972, was abused by Wilde during rugby practice, and also for cricket lessons, fitting the child's protective box, regularly manhandling his private parts as he did it.
After initially denying the allegations, Wilde then decided to plead guilty and later was jailed for two years.
Due to media coverage of the case, three more victims came forward in 2016, all of whom went to Wade Deacon between 1971-1977, with them describing how Wilde had fondled one on a gym beam.
Another man remembered how, as a boy, Wilde had targeted him after the pupil accidentally sucked fluid into his mouth during a science experiment.
A third ex-pupil recalled Wilde inappropriately fitting his cricket box, with the fondling happening five times a week during the three-month season.
When Wilde, of Drake Close, Warrington, was quizzed by detectives he confessed he was a "young and naive" teacher who was "unsure of himself and his sexuality" and admitted the molesting.
He was jailed for 12 months.
The most recent convictions involved a pupil aged 12 or 13, between 1973 and 1976, who was a keen participator in chemistry lessons and answered a lot of questions.
"Leering" and "smiling" Wilde preyed upon this fact, and while the boy was speaking, he placed one arm on his shoulder and another down his leg, onto his genitals.
The sex attack left the youngster asking far fewer questions to avoid being targeted.
Finally, sick of the abuse, the boy plucked up enough courage to grab Wilde's wrist, and shout at him: "F*** off you b******."
Wilde later admitted his crimes and was jailed for six months.
Jeremy Rawson, defending, said his client retired from teaching 10 years ago and was a "low risk of re-offending and to the public."
Wilde, he added, had significant health problems, but admitted the new offences represented a "breach of trust" and an "obvious disparity in age."
The barrister said: "It's a very sad position the defendant finds himself in, he was a well-thought of teacher....helping many students achieve better things.
"It is with great ignominy that he appears at the court for these offences."
Wilde has paid financial damages to some of his victims in civil cases, it also emerged.
Judge Rachel Smith told Wilde, who appeared at Liverpool Law Courts with his wife, although she chose not to enter the courtroom itself, told him: "Clearly, there was a breach of trust in this case.
"It is self-evident the offences were committed around other children and around the school premises."
Wilde, who arrived at court with a bag of his belongings, will have to sign the Sex Offenders Register once more, this time for 10 years.
