The Department for Education’s annual report says the risk of some school buildings collapsing has risen from “likely” to “very likely”, with blocks built between 1945 and 1970 most at risk because of serious structural issues.

No imminent risk to life is present, but officials are stepping up monitoring and scrutiny procedures.

The report says: “There is a risk of collapse of one or more blocks in some schools which are at or approaching the end of their designed life-expectancy and structural integrity is impaired.

“The risk predominantly exists in those buildings built in the years 1945 to 1970 which used ‘system build’ light frame techniques. At the publication there are no open schools or college buildings where we know of an imminent risk to life.”

The report says the risks are “unlikely to reduce in 2022”, as there was no agreed increase in condition funding or in the scale of the rebuilding programme at the 2021 spending review.

Labour has urged the government to tell parents which buildings were affected and to reassure them they are being made safe.

The DfE says the life expectancy of buildings can however be extended by careful monitoring and maintenance. The department has also opened the next round of its school rebuilding programme, which plans to rebuild buildings at 500 schools over the next decade and will prioritise those schools for selection “where there is clear evidence this risk is present”. Last week it announced 239 schools that will benefit.