Called “Johnny lickers” by pupils and “drama poofs” by some teachers, the clique of John Owen’s favoured students adored and feared their charismatic teacher in equal measure.

But Owen, says children’s commissioner Peter Clarke, was using drama at Ysgol Gyfun Rhydfelen, Pontypridd, as a “vehicle for improper activity with children”, by the “consistent introduction of sexual themes into texts, practicals, and practical exams”.

One of his key recommendations is for practical guidance on how drama is taught and examined in schools, which expressly deals with sexual content and language, intimate physical contact and nudity.

Like sport, drama is a subject that can enrich children’s lives and boost their confidence - but it also leaves them vulnerable to abuse, and practitioners need to catch up on the work done on child protection by their colleagues in PE, says Mr Clarke.

His report, on allegations of abuse at the school, is disturbing. A sixth-form girl described hearing another student refuse Owen’s direction that she masturbate a male classmate; another testified that Owen prodded with a stick the private parts of girls who had been asked to blindfold themselves and lie down on the floor with their legs apart.

Owen himself admitted getting two 13-year-old boys “to dance naked during a rehearsal, in a dance that some witnesses described as ‘simulated buggery’”.

But Owen was left unchecked by senior teachers, despite concerns raised by some about his bullying of pupils, and bullied and belittled his younger and less experienced head of department.

Some external GCSE drama examiners halted practicals because of their concerns. But when they reported inappropriate material, such as the use of swear words, to the Welsh Joint Education Committee (WJEC) they were treated “shabbily”.

One never examined for the board again, and the WJEC never collated the reports or passed them to police or social services. Worse still, when some of Owen’s victims eventually found the courage to make statements against him, they were verbally abused by one teacher loyal to Owen, and physically intimidated by another - who had been in a relationship with him.

One pupil was driven from the school as a result. The rest were left largely unsupported after Owen resigned.

Peter Clarke blames Mid Glamorgan education authority’s handling of the 1991 investigation for some of the divisions within the school. Pupils, parents, governors and teachers were left in the dark about the serious nature of the allegations against Owen because of what was effectively a cover-up by the LEA - and Owen was free to continue working with children after his resignation.

In the “bleak landscape” of the evidence presented at Clywch, there was one beacon: the “professionalism and moral courage” shown by acting head Hywel Jeffreys and four senior colleagues.

In 1991, they took statements from pupils and signed a four-page memorandum detailing their serious concerns about Owen, which was passed to the LEA.

Mr Clarke also praises Mrs Lynn Phillips, mother of one of the sixth-formers, who was “tenacious and thorough” in her complaints to the school, the WJEC and the LEA in 1991.

But the protection of children cannot be left dependent on the existence of future Mrs Phillips. So, within three months, the children’s commissioner wants every child in Wales to have been informed of the support available to help them via services such as ChildLine, and for LEAs to have identified a child protection teacher in every school.

He also calls for an independent counselling service for children, the creation of LEA child protection officers responsible for schools, and whistle-blowing policies in every school.

Jane Davidson, education and lifelong learning minister, said the Clywch report was deeply disturbing. She has accepted its broad themes and promised a full response to it and a Welsh Assembly debate immediately after the summer recess.

Key recommendations

* Four independent tribunals chaired by lawyers to hear serious allegations of abuse against teachers.

* Review of examining boards’ child protection policies.

* Whistle-blowing policies in every school.

* Initial and in-service training for teachers on identifying abusers and child protection.

* Independent counselling service for children.

* Children to be informed of work of organisations like ChildLine.

* Child protection co-ordinators with special responsibility for schools in every local education authority, and LEAs to lead investigations.

* A teacher and governor in every school responsible for child protection to be identified.

* Child protection policies for Welsh media.

* Practical guidance on how drama is taught and examined.

* Review of personal and social education.