Peter C has been accused by three mothers, Angela Napoli (33), Venhar Fontana (41) and Rose Scalise (37), of indecent behaviour at the school in Wettingen, Zurich, online news website 20 Minutes reported.

“He used perverse language with the sixth graders and told them they had to watch pornographic films for homework,” the mothers said.

Scalise also claims that Peter C touched her daughter’s bottom on one occasion, and that he encouraged strip poker during class.

“He looked on passively as a girl in the class took her trousers off,” Scalise told the website.

With a previous class, it has emerged that he also played strip poker with pupils during what should have been an arithmetic lesson, sources told 20 Minutes.

Headmaster Martin Villing said he had not been aware that this behaviour had been going on with the current class, but assured parents in November that he would do something about it.

In February, when still no action had been taken, the parents approached the school board.

“A possible paedophile has been teaching our children for months and nothing has happened,” the angry mothers said.

Thomas Sigrist, president of the Wettingen school board, confirmed that Peter C has been on sick leave since early March. The official reason for his absence is burn-out.

One of the affected pupils has now been transferred to a school in a neighbouring village.