A school in Oxfordshire is being forced to close due to unsafe concrete, despite previously reassuring parents it had not been affected by the crisis.

John Mason School in Abingdon will be shut on Monday (September 11) as a result of finding reinforced autoclaved aerated concrete (RAAC) on its site.

The school is in "urgent contact" with the Department for Education to discuss "the next steps".

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In a letter to parents, Abingdon Learning Trust said: “I wrote earlier this week regarding RAAC in our schools and at that point we believed that we had no RAAC identified from our 2023 condition survey.

“Unfortunately, we now have further information and there is RAAC at John Mason School.

“The Department for Education (DFE) guidance is very clear that where RAAC has been identified, schools should restrict access to those spaces and restrictions must remain in place until mitigation has taken place.

“We have been in urgent contact with the DFE. We are waiting on their guidance as to the next steps.

“In the meantime we are closing the school on Monday, while we explore how to ensure that education for students can be provided effectively and ensure that RAAC concerns are addressed.”

It added that the school would be in touch about arrangements for students from Tuesday (September 9) onwards.

RAAC is most commonly found on flat roofs, but it has also been identified in outdoor wall panels, indoor wall panels and ceilings.

In total, 140 schools across the country have been forced to either close completely or partially shut buildings over the unsafe concrete crisis.

RAAC was a low-cost, lightweight building material that was used in the construction industry between the 1950s and mid-1960s.

Three academy schools in Oxfordshire were initially thought to have been affected by RAAC.

Larkmead School in Abingdon, Wallingford School and Hardwick School in Banbury were all identified, but Larkmead has since confirmed that they do not have RAAC at its site.

All three schools remained open, with measures in place to alleviate disruption from the crisis.

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A spokesperson for Oxfordshire County Council said on September 6: “Only one Oxfordshire secondary school is a local authority-maintained school, and around half of primary schools in the county are now academies.

“These schools are therefore run independently of the council and managed by the Regional Schools Director or Department for Education.

“The county council has been kept informed by a small number of academies in the county who do have RAAC issues but who have each come up with arrangements to ensure that children continue to be educated.

“Parents were fully informed of the individual situations at these schools by academy trusts earlier this week. The county council will help each school where it can.”