Rishi Sunak was under fresh pressure over his role in the concrete crisis after a minister said the former chancellor approved funding for the rebuilding of 50 schools yearly, despite a bid for 200.

Schools minister Nick Gibb suggested on Tuesday that the Prime Minister, when chancellor in 2021, had gone with other priorities over a request to increase funding to fix England’s schools.

The Department for Education (DfE) conceded that just four schools have been rebuilt so far under the programme to overhaul 500 sites by 2030 that Mr Sunak has used in his defence in recent days.

Mr Gibb insisted the Government’s response to the reinforced autoclaved aerated concrete (Raac) that is causing more than 100 schools to partially or fully shut is “world-leading”.

The Prime Minister told the first meeting of his Cabinet since the summer break that ministers were “doing everything possible to minimise disruption in the small portion of schools which are affected”, No 10 said.

Education Secretary Gillian Keegan was among those around the Cabinet table after being caught on camera hitting out at others she argued had “sat on their arse and done nothing” as she tackled the crisis.

The Prime Minister has been accused of refusing to fully fund a programme to rebuild England’s crumbling schools when he was chancellor by former DfE permanent secretary Jonathan Slater.

The ex-civil servant said that up to 400 schools a year needed to be replaced but that funding was given for 100 after Mr Sunak took the decision to “halve the size of the programme”.

However, Mr Sunak told reporters the attack on his record was “completely and utterly wrong”.

Mr Gibb said he did not recognise the 400 figure but admitted that the DfE asked for funding to overhaul 200 schools a year in 2021 only for Mr Sunak to agree funding for just 50 a year.

“We put in a bid for 200, but what Rishi agreed to was to continue the rebuilding programme with 50 a year, consistent with what we’d been doing since we came into office,” the minister told Sky News.

“Of course we put in a bid for 200, but of course the Treasury then has to compare that with all the other priorities from right across Whitehall, from the health service, defence, and so on.”

The school rebuilding programme has completed four sites so far, the DfE said, but officials expected the pace to pick up by the end of the decade.

Mr Sunak has pointed to that programme to rebuild 500 schools as “one of the first things I did as chancellor” as he sought to defend himself from Mr Slater’s allegations.

A DfE spokeswoman said: “We have committed to rebuilding 500 schools under the schools rebuilding programme between 2020 and 2030 and are on track to deliver that commitment.”

Downing Street however insisted it was not the only scheme tasked with fixing schools, saying in total 72 were completed in 2021 and 47 the following year.

Mr Gibb defended Ms Keegan after she apologised for accidentally expressing her frustration on camera that no one was acknowledging what a “f****** good job” she was doing.

He told BBC Radio 4’s Today programme: “What she was trying to get across is the huge amount of work that the DfE has done.

“We are world leading in terms of identifying where Raac is in our school estate.

“We’re talking about a small number of schools out of 22,500 schools, but we have conducted surveys since March last year, so we know where Raac is, and we’re sending in surveyors to identify Raac.”

After apologising for her language, Ms Keegan went on to admit to being on holiday in Spain in the run up to ordering the 104 schools and colleges to make closures.

She also said she was “really sorry” for the way the decision to close schools was announced just days before the start of term and that she “would have done anything to avoid it”.

“I had to make a decision right at the end of August, which was the worst time to make the decision,” she said on BBC Radio 2.

She was mocked on Tuesday for tweeting a graphic saying “most schools unaffected” by the Raac crisis, with Labour quick to post a spoof saying “most beachgoers not eaten by big shark”, in reference to the stance of the mayor in the movie Jaws.

Labour was also highlighting that Mr Sunak’s 2021 budget that did not fulfil the school rebuilding fund request included a tax cut on champagne, with the Opposition adding: “This is what Rishi Sunak prioritises.”

Ministers have been accused of taking a “sticking plaster approach” to essential maintenance by the head of the Whitehall spending watchdog.

Writing in the Times, National Audit Office chief Gareth Davies suggested that there had not been sufficient focus on “unflashy but essential tasks” such as maintaining public buildings that have faced “underinvestment”.

Mr Gibb said he did not “accept” the charge, telling Sky News: “We’re spending £1.8 billion a year… and we are taking more proactive action on that than any other government in the world.”

Labour leader Sir Keir Starmer said it was “unforgivable” that children were missing the start of term due to the crumbling concrete crisis.

Opening a meeting of his reshuffled shadow cabinet, Sir Keir said: “Children are not at school today because of the action the Government has failed to take in relation to schools. That is unforgivable.

“It is a metaphor, frankly, for their sticking plaster politics: never fixing the fundamentals – always sticking plasters.”