Teachers on strike from Forest Hill School took their picket line to the Department for Education (DfE) to demand emergency funds.

The National Union of Teachers said that Forest Hill School, in Dacres Road, had been instructed to recover an estimated £1.3million deficit.

It said 15 teachers are being made redundant and 23 are reportedly resigning "rather than go through redundancy procedures or accept proposed changes".

Phil Beadle, a parent at the school said: “Parents, staff and the council all agree that the education of the boys at Forest Hill is paramount.

"As parents, we believe these draconian cuts can only have a negative impact on the educational outcomes of the boys and on the lives of profoundly valued members of the community: our children’s loved and respected teachers.”

Staff at the school have been on strike nine days so far this academic year.

In a letter sent to parents on June 15 headteacher Mike Sullivan said: "We have reorganised our teaching staff structure for September. The new structure has 15 fewer posts and in addition to this reduction we have some staff leaving for their own professional reasons.

"The turnover includes the 15 lost posts and so is higher than our norm, which has been seven to 10 teachers in the recent past."

Saraid Dodd, NUT representative at the school, said: “We are chanting ‘not our deficit, it’s our school don’t mess with it.’ Our students deserve better than this. We are striking to defend our school and to make clear to local and national government that we believe the value of education goes beyond numbers on balance sheets.”

Martin Powell-Davies, London NUT representative said: “Schools are already struggling to retain good qualified teachers due to workload. DfE should help Lewisham Council and all financially struggling schools to secure funding to protect good education for all pupils.”

A spokesman for Lewisham Council said: “We are doing everything we can to support the headteacher and chair of governors of Forest Hill School to raise standards and bring the budget back onto a secure financial footing.

"Talks are progressing between Forest Hill School and the unions and we hope these talks will result in an agreement that avoids further strike action.”

A Department for Education spokesman said: “We want to make sure all children, regardless of where they live or their background, can get a world-class education that unlocks talent and creates opportunity. Thanks to our reforms there are 1.8 million more children in schools rated good or outstanding than in 2010.

“The core schools budget has been protected in real terms since 2010 and is set to rise from £40bn in 2016-17 to £42bn in 2019-20 with increasing pupil numbers. But we recognise that schools are facing cost pressures and will continue to provide support to help them use their funding in cost effective ways.”