Teachers and staff at The Kimberley School plan to walk out for three more days next week after negotiations with the headteacher broke down.
The National Union of Teachers (NUT) said it had offered to suspend strike action in return for the school postponing its planned conversion to academy status.
But joint secretary of the Nottinghamshire branch Liam Conway said after the meeting with Chris Teal on Tuesday: “The NUT is very disappointed at the belligerent stand of the head and governors at The Kimberley School on this matter.”
Strikes took place on Wednesday and Thursday with pickets outside the school each morning. Teachers are also set to walk out on Monday, Tuesday and Wednesday next week.
Mr Conway added: “We were told that all schools would soon be academies and that resistance was pointless.”
He called on the governors to consult with all parties on academy status. He said the NUT remains open to negotiations and offered to meet with management at any time.
Mr Teal said: “The governors are absolutely clear that academy status is the best way forward for this school.”
He said it was ‘high time’ the NUT listened to the governors and claimed to have received calls from parents who support the school’s decision to convert.
The school remains open for students with exams on the strike days. Call 0115 938 7000 for more information.