Five trustees who ran an east London academy where a teacher tried to radicalise pupils have been disqualified from any similar roles.
The Charity Commission investigated Essex Islamic Academy in Barking after Umar Ahmed Haque was convicted of terrorism offences last year.
It found the trustees had failed to safeguard pupils who were shown videos created by the Islamic State group.
The Essex Islamic Academy has been approached for comment.
Haque was initially recruited as an administrative assistant by the academy but he later began teaching classes unsupervised to about 80-100 children.
The Old Bailey previously heard he showed "violent and graphic" footage to children as young as 11 as part of attempts to train an "army of children" for terrorist attacks.
The Charity Commission found the trustees did not check what Haque was teaching and had not applied for an enhanced DBS check which was required for his teaching role.
"Ultimately the inquiry established that no due diligence was carried out prior to Haque taking up employment," the commission said.
Investigators also found the trustees initially withheld the fact that Abuthaher Mamun, who assisted Haque in his classes and was later also convicted of terror offences, had worked at the charity.
Michelle Russell, director of investigations, said children at the academy "were let down" by the trustees, who have all been banned from holding trusteeships for 10 years.
A new board of trustees have been appointed, after the commission installed an interim manager at the academy in June 2018.