The allegations were made to Tusla by former student Páidí Manning, and related to incidents that took place between 2001 and 2003. 

These included allegations that his former teacher had instructed an older student to assault him with a T-square, and that he had forced him and fellow boarders to stand outside in underwear as “punishment”. 

In 2023, Tusla determined Mr Manning's allegations against Mr Condon to be 'founded'. 

According to Tusla, 'founded' means it established, on the balance of probabilities, that abuse did occur.

Mr Condon was appointed principal of Belmayne Community Special School on its opening last November.

Following a meeting with the school’s patron, Dublin and Dún Laoghaire Education and Training Board this week, parents thanked Mr Manning for “his bravery and commitment to alerting us on serious matters”.

The group also thanked teachers and special needs assistants in the school, and said parents have been given assurances a full internal investigation is underway. 

The school has faced "significant difficulties from the outset", it added. 

“A special school for children with autism and complex needs, many requiring a very high level of care and support, was opened without the adequate systems, supports, and resources fully in place,” they said in a statement. 

“As a result, our children and families have experienced reduced school hours due to staffing issues, unwarranted suspensions in absence of consistent behaviour support plans, school injuries, and a lack of appropriate supports.”

The group called on minister of state Michael Moynihan, children's minister Norma Foley, and education minister Hildegarde Naughton to address "serious failures within many systems".

Multiple attempts were made to contact Mr Condon. 

A spokeswoman for the Department of Education said it does not comment on individual cases but “takes child protection very seriously and considers that the protection and welfare of children is a fundamental responsibility of all involved in the care and education of children".

A spokesman for Tusla said it does not comment on individual cases but said it uses its child abuse substantiation procedure “for the purpose of protecting children who could be at risk of abuse today, and not to decide if a criminal offence has been committed; that is for the gardaí to investigate”.

Dublin and Dún Laoghaire Education and Training Board said it is "following appropriate policies and procedures and will ensure supports are in place for the school community”.