A school in Dagenham faces strike action over plans to make pay cuts and demotions.
Staff at Valence Primary - which has sites in St George's Road and Bonham Road - are due to walk out on Wednesday, June 30.
Almost half of workers face reduced salaries, according to the National Education Union (NEU).
Dominic Byrne, NEU secretary for Barking and Dagenham, said: "We are very disappointed that we have had to call members out on strike. The school’s plans are unnecessary and misconceived."
He added if talks fail with the conciliatory service ACAS, members will go ahead with the action.
The school's chair of governors, Avril McIntyre, said the primary is doing everything it can to resolve the issue and is being flexible in its approach, urging the union to follow suit.
"We regret this disruption to the education of our young people, who have already been affected by the pandemic.
"This further loss of education for a management restructure is definitely not in the interests of our children," she said.
The school maintains the changes are part of a management restructuring which would not come into effect until 2024.
It argues a significant drop in pupil numbers has seen its funding cut to the point where it cannot afford to continue current pay levels.
Ms McIntyre said the changes would affect 15 staff members out of 46, with some pay cuts and demotions, but no forced redundancies.
The disagreement centres on pay rewards for extra responsibilities undertaken by teachers.
The primary wants to bring their number, level and value in line with similarly sized schools. But the NEU says the savings amount to less than £50,000 a year.
Mr Byrne said: "In a large school, this could easily be found through agreement, but all the staff’s suggestions to avoid pay cuts and demotions have been rejected.
"Valence Primary provides excellent teaching and learning but pay cuts and demotions will lead to experienced staff leaving and that will be bad for the children and school."
He added "management intransigence" left NEU members with no other choice than to call a strike.
Unless agreement is reached, the NEU also threatens strikes on July 7, 8, 13, 14 and 15.
Mr Byrne said: "Support for the strike is strong and we expect the school will be closed on every strike day."
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