A Tory minister was skewered by Naga Munchetty as he struggled to defend the government over the closure of unsafe schools just days before the end of the summer holidays.

More than 100 will have either partially or completely shut their doors to pupils because the concrete used to build them – known as RAAC – is at risk of collapse.

Schools minister Nick Gibb this morning admitted that some of the affected schools have yet to be contacted by the government, and that it is still not known how many will have to close completely.

Appearing on BBC Breakfast, Gibb was grilled on the government’s response to the crisis, which will see thousands of pupils forced to learn from home when the new term starts next week.

The minister insisted the government had been “very proactive in assessing the school estate” and had taken action as soon as the extent of the problem became apparent.

He said RACC was used between the 1950s and 1990s, and that surveys were sent to every school in England in 2022 asking whether it was present in their buildings.

But Munchetty told him: “I’m sorry, please let me interrupt. You’ve given me the history of RACC and the dangers known.

“In 2018 when there was a national audit report saying that it was in 572 schools, why did it take until 2022 until surveys were sent to schools?”

Gibb said “warning notices” had been sent to all schools after that report, but that further evidence had emerged since then about the dangers posed by the crumbling concrete.

He added: “You seem to be criticising us for being more proactive than other governments around the world.”

The minister said that prior to yesterday, the government had already taken action in 52 schools where RACC was identified.

Munchetty said: “Is it fair to say that they were unsafe up until that point – that children were attending schools with buildings unsafe?”

Gibb replied: “This evidence was emerging over time …”

The presenter then interrupted to say: “It’s a simple yes or no, isn’t it? They were either safe or unsafe.”

The minister said: “Well we felt, having had that evidence, that parts of the school that had RACC that was in a criticial condition were not safe.”

“So they could have potentially collapsed?” Munchetty replied.

Gibb said: “Yes and that’s why we took action.”

Labour has accused the government of “staggering incompetence” in not taking action until just before schools return from the summer break.

Shadow education secretary Bridget Phillipson said: “Ministers have been content to let this chaos continue for far too long.”

Mike Short, head of education at the UNISON union, said the situation was “nothing short of a scandal”.