The education secretary, Gillian Keegan, has branded those raising questions about her handling of the crumbling concrete crisis in schools “sensationalists”. At a behind-closed-doors drinks reception co-hosted by the “Conservatives in communications” network on Wednesday night, Keegan continued to brush off criticism about the government changing its advice to schools days before the autumn term began. After being forced to apologise for lamenting that no one had praised her for “doing a fucking good job”, she joked she might need fresh media training to avoid further hot mic moments – but added to laughter: “I don’t want to learn how to stop swearing.” Keegan described the move that precipitated the partial or full closure of approximately 100 schools because of concerns about outdated material – known as reinforced autoclaved aerated concrete (Raac) – as the “worst decision, honestly, that anyone will ever have to make”. Although Keegan referenced three recent ceiling collapses triggering her decision, she appeared to take a swipe at how the issue had previously been bounced around Whitehall. Keegan said: “In government, people quite often write down what other people should do, and it gives them the problem. Without the cash, funnily enough.” Her comments came after Jonathan Slater, formerly the most senior civil servant at the Department for Education (DfE), accused Rishi Sunak of cutting the budget for school repairs. Slater said that despite officials warning there was a “critical risk to life” because of the Raac issue, with 300 to 400 school rebuilds needed a year in England, Sunak as chancellor only gave funding for 100, which was then halved to 50. Keegan said that despite the “bad press” she had received this week, “it really hasn’t bothered me that much”. She continued: “I’ve been quite resilient because I know I made the right decision.” In a further attack on the media coverage of her handling of the Raac issue, Keegan added: “They’re not journalists, they’re sensationalists.” After the guidance to schools was changed, Keegan said she was keen not to “outsource the problem to schools or to anybody else”. She recalled having had to “stand up caseworkers, project directors, Portakabins, all the practical things”. Keegan made mirth of pictures taken of her outside Downing Street this week, which she described as “Devil Wears Prada does politics”. “I went up to the paparazzi with the picture and I said: ‘Which one of you took this?’ And they’re all shit scared of me … “And then one of them sort of went ‘Me’ and I said: ‘Right, all you, follow him because this guy is fantastic. That’s what you want to be doing, not those other ones you’ve had in where I look terrible.’” Earlier on Wednesday, the DfE published a list of the 147 schools and other education settings in England known to contain Raac, affecting more than 100,000 students. Essex is the local authority with the highest number of schools affected, with 53 settings on the list, accounting for more than 30,000 students, close to a third of all affected pupils. Speaking at prime minister’s questions on Wednesday, Rishi Sunak said the government was doing everything it could to fix the situation quickly and minimise disruption to children’s education. He stressed that the decision to order more than 100 schools to partly or wholly close shortly before the start of term was made as a result of fresh concerns about the safety of Raac-built structures. He added: “We make no apology for acting decisively in the face of new information.”