Education unions are calling on a school to scrap plans to become an academy as the resignation of senior staff has left it without a “democratic mandate”.
Worthing High is in the final stages of the move, which has encountered strong opposition from parents and teachers.
In May the school’s governing body voted to apply to the Department for Education for academy status.
But since then a number of high-profile members of staff and governors have resigned – including the former head Alison Beer.
The unions are now calling on the school to put those plans on hold and instead focus on teaching.
In a joint statement, signed by representatives of the ATL, NASUWT, NUT and UNISON, they said: “The outgoing head teacher voted with the governing body for the school to convert in May.
“Since then, a number of governors have resigned, which taken together with this latest resignation, leaves the school without a democratic mandate for academy conversion.
“For months we have been saying that the basis for this school’s conversion is weak and it remains so.
“The central claim, that the school would be better off financially, just doesn’t stack up.”
An anti-academy group has staged a number of protests over the past few months which culminated in a teacher strike before the school broke up for the summer holidays.
However, senior staff at the school maintain that there is limited opposition and say that the anti-academy group is made up of a small group of politically minded people.
Eric Skyte, NASUWT member said: “The school must call an emergency meeting of the full governing body and put a stop to this damaging conversion.
“The students and their parents deserve better.”
The school is due to convert on December 1.