Teachers at a Somerset school have voted to strike over bullying and harassment claims of staff.
The National Teachers' Union (NUT) said it was also worried about workloads, maternity rights and the lack of support for newly-qualified teachers at Academy of Trinity School, in Radstock.
Parents have also removed 27 children since 1 September, though some because they were moving home.
The Dove Family Trust, which runs the school, said it would comment later.
Complaints 'rigorously' assessed
NUJ regional secretary Andy Woolley, said: "This is extremely worrying - most people will know most schools are much more stable than that, even in the current climate where teachers are leaving the profession because of workload pressures.
"We've taken out some grievances for existing members of staff, we've got former members of staff coming forward complaining about how they were treated."
In 2013, the school was rated as outstanding by the education watchdog Ofsted.
According to the Department for Education website the school had 223 pupils in January 2015.
Ofsted said it did not comment about individual schools, but a spokesman added: "All complaints received will be rigorously looked at and dealt with as quickly as possible."
As an academy school, Academy of Trinity reports to the Department for Education, which has not commented, although the BBC understands it has called for an independent review.
'Sacked over grievance'
Bath and North East Somerset Council confirmed it had received applications for 27 pupils from the school to be transferred.
The NUT also carried out a Freedom of Information (FoI) request which found 20 teachers had left the school in the past three years.
Since that request was made, a further three have left, including two who were sacked after they took a grievance out, the NUT said.
The union said it wanted to resolve the issues with the school and hoped to avoid strike action.