Headteachers have written to the government saying they are “deeply concerned” by proposed changes to the schools budget and called for the needs of schools in deprived areas to be at the heart of any plans.

Secretary of state for education Justine Greening was told in the letter how Newham’s schools have managed to succeed in spite of being in the 23rd most deprived local education authority in England, but changes to the formula used to work out how much money they get threatens to undo that work.

They identified £8m worth of cuts as the largest reduction of all London boroughs and stated the plans would be “a significant obstacle” to youngsters improving their prospects in the face of “huge disadvantages”.

The school leaders went on to outline how “soaring costs”, “rapid” increases in the cost of living and a funding shortfall of eight per cent per pupil by 2020 would make it difficult to hire and keep hold of staff.

Also signed by Sir Robin Wales and cabinet member for children and young people Cllr Rev Quintin Peppiatt, the letter ended by urging Justine Greening to make sure no school in a poor area would lose out as a result of the plans, which are under public consultation until March 22.

School standards minister Nick Gibb defended the plans in an earlier statement saying: “We recognise schools are facing cost pressures, which is why we will help them use their funding in cost effective ways without affecting educational outcomes.”

To have your say on the plans go to consult.education.gov.uk