In 1956 he had accused Catholic clergy of sexually abusing him in his Church run care home.

Two clergymen were convicted of abuse but Mr Heithuis, a victim, was nonetheless transferred by police to a Catholic psychiatric hospital before being admitted to the St. Joseph Hospital in Veghel later that year.

There, court papers confirm, he was castrated “at his own request”, despite no submission of his written consent. Sources told Mr Dohmen that the surgical removal of testicles was regarded as a treatment for homosexuality and also as a punishment for those who accused clergy of sexual abuse.

Cornelius Rogge, 79, a well-known Dutch sculptor whose family knew Mr Heithuis in the 1950s, reported the castration to an official inquiry into abuse within the Catholic Church. But his evidence was ignored.

“We once asked Henk to drop his pants when the women were gone. He did that. He was maimed totally. It was a huge shock,” he said.

Last December, an official investigation by Wim Deetman, a former Dutch minister, received 1,800 reports of sexual abuse by clergy or volunteers within Dutch Catholic dioceses in the period since 1945.

The Deetman inquiry received a report of the Heithuis case from Mr Rogge but it was not followed up because “there were few leads for further research”.

Evidence emerged on Monday that government inspectors were aware that minors were being castrated while in Catholic-run psychiatric institutions.

Minutes of meetings held in the 1950s show that inspectors were present when castrations were discussed. The documents also reveal that the Catholic staff did not think parents needed to be involved.

There are also allegations that Vic Marijnen, a former Dutch Prime Minister, who died in 1975, was linked to the case.

In 1956, Mr Marijnen was the chairman of the Gelderland children’s home where Mr Heithuis and other children were abused. He intervened to have prison sentences dropped against several priests convicted of abusing children.

Dutch MPs will today call for a parliamentary investigation into the allegations.

“I am shocked that boys were being castrated in the 1950s,” said Khadija Arib, a Labour MP. “I want an independent investigation. We must find out how many cases there were, who knew about it and why the government did not act.”