The trustees of a mosque where children were groomed for terrorism failed to properly monitor an Islamic State sympathiser then attempted to cover up what happened, the Charity Commission has found.
All five have been disqualified for 10 years as a result of the inquiry into the Ripple Road Mosque, also known as Essex Islamic Academy.
Islamic State fanatic Umar Ahmed Haque, from Forest Gate was found guilty of terrorism offences in March 2018 and jailed for life with a minimum term of 25 years after grooming children as young as 11 at the mosque.
The Old Bailey trial heard how the 25-year-old secretly brainwashed the boys through terrorism role play and exercises, and showed them gory IS propaganda.
He had told the children he intended to die a martyr and bragged about recruiting them in the months before his arrest.
One of the youngsters later told police that Haque wanted a group of 300 men and was training the boys to be strong enough to fight.
Jurors also heard how Haque had also planned to use guns and a car bomb to strike 30 high-profile targets including Big Ben and the Queen's Guard.
The Charity Commission's inquiry established Haque was originally recruited as an administrative assistant but had been teaching classes unsupervised in the charity's madrassah - or religious school - which was attended by as many as 100 five to 15-year-olds a day.
The inquiry found no evidence that the trustees had applied for an enhanced DBS check on Haque - which would have been required for his teaching role - and the trustees also admitted there was no supervision over his adherence with the madrassah's syllabus.
The commission also revealed Haque was assisted in his classes by Barking man Abuthaher Mamun, who was 19 when he was jailed for 12 years.
The trustees withheld the fact that they had been aware of his involvement until the commission used legal powers to require them to answer questions and supply documents.
The inquiry also established that a number of responses provided to it by the former trustees turned out to be false or misleading, including in relation to pre-employment checks carried out on Haque.
The charity commission issued an order to prevent the trustees from running any education classes or recreational activities until a number of safeguarding terms were met.
It found that the actions of the former trustees amounted to serious misconduct and mismanagement in the administration of the charity.
The inquiry considered their competence, honesty and integrity, and concluded that they were unfit to be charity trustees.
All five have been banned from serving as trustees or senior managers of a charity in England and Wales for 10 years.
Michelle Russell, director of investigations, monitoring and enforcement at the Charity Commission described it as "the worst case we have seen".
She said: "I, like the public, am appalled by what happened here to these children who should have been in the safe custody of this charity - being exposed to harm through attempted radicalisation and terrorist material.
"The two individuals have been held to account through criminal proceedings, and it is right that we have, on behalf of the public, held the individuals who were trustees at the time of his actions, responsible for their failures.
"The public rightly expect trustees to honour their positions of responsibility, demonstrating unfailing care for the people they are meant to support.
"These individuals proved themselves to be wholly unsuitable; what happened on their watch is deeply alarming and troubling, running counter to everything people expect of charity."
The commission has said that since its intervention, there have been significant improvements in the charity's governance and safeguarding procedures.
The interim manager implemented a series of new policies and procedures, including around protecting people.
They have appointed a new board of trustees and ensured that they fully understand their responsibilities as trustees, including safeguarding.
Ms Russell added: "Our inquiry's actions have set important foundations for the good governance of this charity going forward.
"Clearly, what went on here will not just have affected the children that were abused, but their families and the community as a whole. The charity's new leadership has to continue rebuilding vital trust."
The Essex Islamic Academy has been contacted for comment.
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