Shore School headmaster Tim Petterson has been dismissed after the school’s governing council said a review of culture had found new leadership was needed.

Former St Andrew’s Cathedral School head John Collier has been appointed interim headmaster while a new principal is found.

The decision comes amid deep divisions among staff and parents at the 133-year-old Anglican school over Petterson’s educational leadership and management style. Since he began in 2020, more than 90 staff members have left.

Earlier this year, Petterson admitted his leadership had left teachers sad, angry and fearful in a long apology to the school’s staff, saying he had been unintentionally “disrespectful, insensitive and unwise”.

The apology came after teachers wrote to the school’s governing council about their concerns, which included low staff morale. Concerns were also presented to the Anglican Archbishop of Sydney, Kanishka Raffel.

Critics also argued he had insufficient experience to transform Shore, which was founded by an act of parliament and has an income of $65 million annually.

Last term, the council hired consultant Rhonda Brighton-Hall to review the leadership culture of the school, identify reasons behind the divisions, and explore the concerns about Petterson’s leadership.

The review involved confidential interviews, written submissions and an anonymous survey and was presented to the chair of the council, Bay Warburton, late last term.

Petterson was informed of the council’s decision this week as the school was preparing to welcome boys back for term three. The school community is being told on Friday.