A former Falmouth man who was involved with two theatre groups and an Army cadets unit has been jailed for four years after being found guilty of indecently assaulting two young boys and a girl.

Ivor Trevillion, a 53-year-old said by Judge Christopher Elwen to have a predeliction to prey on young boys, was convicted by a jury on five charges dating between 1994 and 2000. He was acquitted of two further charges.

Trevillion had denied the allegations – describing them as “malicious nonsense”.

When prosecutor Philip Lee in cross-examination accused him of having lied to the jury, he exploded: “How dare you, sir. I did not do these things. How many times have I to say this?”

But his protestations were in vain. The jury of eight women and four men was in retirement for less than three hours before returning their unanimous verdicts.

Sentencing Trevillion, who lives in Alexandra Road, Plymouth, and has been a volunteer working with the local police young offenders’ unit, Judge Elwen said his offending had involved elements of grooming and a very significant breach of trust.

He ordered that Trevillion should sign the sex offenders register for the rest of his life and imposed a Sexual Offences Prevention Order which disqualifies him from working with children and severely restricts his contact with them unless they are in the company of parents or guardians.

After Trevillion had gone down to the cells, DC Garry Hainsworth, who led the police investigation, said he had been a predatory child abuser operating in both the Falmouth and Plymouth areas over a long period of time.

“The families have had to deal with this for two years and I hope that the victims will now be able to move on with their lives,” he said. “I am pleased with the sentence. The police will always do all they can to prosecute anyone who poses a risk to society.”

When Trevillion went into the witness box he said that in the early 1990s, after his mother had died, he had been a heavy drinker, a chronic alcoholic, and his life had been hell. He had now stopped drinking, “but the damage has been done”.

He was a stage hand during a production in Falmouth but was never a chaperone to the children.

Referring to the boy he was alleged to have groped backstage, he told the court: “I never went near him or any of the other children.”

Trevillion alleged that children in the street had called him a “nonce, paedophile and kiddy fiddler” and had made his life hell for six years. They were lying and he had ignored them and walked on.

“I cannot understand the bitterness. It is not true – I have not done any of the things they have said,” he declared.