The Methodist Independent Schools Trust (MIST), which owns Culford School, near Bury St Edmunds in Suffolk, has filed a serious incident report to the Charity Commission.

This follows the sacking of the school’s headmaster Julian Johnson-Munday earlier this week following an independent investigation.

Culford is a co-educational private boarding and day school for children aged one to 18.

A letter sent to parents by Mark Donougher, chairman of governors, said an investigation by an independent lawyer has found that Johnson-Munday breached several the school’s internal policies which constituted “gross misconduct and a breach of trust that was incompatible with his leadership role”.

However, the school has emphasised that the allegations did not concern pupils.

A spokesman from MIST said: “This was not a decision taken lightly and we are all saddened by it. However, his actions rendered his remaining in position untenable.”

A Charity Commission spokesperson said: “We can confirm that in line with our guidance, the Methodist Independent Schools Trust has filed a serious incident report relating to a former employee at Culford School. We have engaged with trustees on this matter and are assured that appropriate steps are being taken by the charity at this time.”

Mr Johnson-Munday had been suspended since earlier this year while an investigation was carried out, followed by disciplinary and appeal processes.

Donougher’s letter said: “We recognise that this has been an unsettling time for our community and we are sorry for the frustration this has caused.

“However, the investigation, disciplinary and appeal processes took time to complete. As we are sure you will appreciate, it would have been both inappropriate and prejudicial to communicate about these matters until these processes had fully concluded.”

Rory Parker will become acting head of the prep school and Victoria Steers has been appointed head of pre-prep.

A school spokesman said: “We are saddened by this decision which was only taken after a thorough investigation and a rigorous disciplinary and appeals process. The allegations under investigation neither concerned pupils nor have they impacted the school’s financial position which remains robust.”