Free school meals for some primary school children in Newham could be under threat, a headteachers’ union has warned.

In a letter sent out on behalf of the Newham branch of the National Association of Head Teachers (NAHT) on Friday, parents were told “rising costs and a frozen budget mean tough decisions will have to be taken”.

Union officials wrote that the ‘Eat for Free’ programme was “unsustainable” in part due to a new “transparent” funding formula from the council – calculated on the number of children and meals served – asking schools to foot 60pc of the bill moving forwards.

“Schools will not be able to continue to provide free meals for all junior aged pupils unless the national funding picture changes, or the mayor decides to fully fund his initiative,” the letter stated.

The Recorder has learned that several schools are seriously considering axing the programme.

At present, more than 15,000 pupils who would not have otherwise qualified for a subsided or free meal receive one, according to 2016/17 council figures.

The council has long prided itself on being one of only three local authorities in the country to offer a universally free school meal scheme to junior schools as part of a promise by Mayor of Newham Sir Robin Wales.

They save families living in one of the country’s most impoverished boroughs more than £500 a year per child.

Research has also shown that children from poorer backgrounds who receive free meals do better in class.

Newham NAHT branch secretary Gary Wilkie said more pupils were becoming eligible for the scheme due to changing benefits.

He said: “School leaders are absolutely aware it is very difficult times for Newham residents and this scheme has helped them but as we move into this time of minimising resource, we have to discuss measures that would not be there in other local authorities.”

Cllr Dianne Wallis OBE, a former headteacher at Oliver Thomas Nursery School for 12 years, said it had come “as a surprise as a member of the council” that schools were paying in at all.

While she welcomed great transparency, she said it was “not a good time to be asking for more money” and the new formula would mean “free school meals or a member of staff” for some schools.

A Newham Council spokeswoman said schools would not pay more on average and while the council recognised their “significant financial commitment”, the current economic climte meant a review was needed to “ensure sustainability and value for money”.

She added: “We will work with schools to review how these programmes are funded to ensure the best outcomes for the borough’s children and young people.”