The two most senior civil servants in the UK exchanged messages describing those inside Boris Johnson’s Downing Street as “poisonous”, “mad” and unfit to run the country, the Covid inquiry has heard. “I’ve never seen a bunch of people less well-equipped to run a country,” Simon Case, then head official in the Cabinet Office, wrote in July 2020 to Mark Sedwill, the cabinet secretary. Case, who took over Sedwill’s role two months later and is still cabinet secretary, also recounted telling Johnson that many senior officials did not want to work in Downing Street “because of the toxic reputation of his operation”. The exchange, which was shown to the inquiry during evidence from Edward Udny-Lister, Johnson’s chief of staff during the pandemic, further highlights the seemingly toxic atmosphere inside No 10 during the period. In his own testimony, Lord Udny-Lister confirmed that Johnson at one point talked about being injected with Covid on TV to show it was not harmful, and later in the pandemic said he would rather “let the bodies pile high” than impose a new lockdown. Case, who had joined the No 10 staff in May 2020, wrote to Sedwill: “At this rate I will struggle to last six months. These people are so mad. Not poisonous towards me (yet), but they are just madly self-defeating.” Sedwill replied: “You’re OK so far because you’ve been around for the good news phase. Wait until there are more Leicesters [where local restrictions had been imposed as Covid cases soared] and the fur will fly. Watch yourself.” Sedwill added: “As I pointed out to Eddie [Lister], it’s hard to ask people to march to the sound of gunfire if they’re shot in the back.” Case then told Sedwill that Johnson had asked him who would replace Tom Shinner, another senior official working inside No 10 on Covid, adding: “I was quite direct in telling him that lots of the top-drawer people I had asked had refused to come because of the toxic reputation of his operation.” The exchange did not make it plain who the pair were referring to, or if they meant only fellow officials and staff, or also politicians. Asked if the messages were a “fair reflection” of the situation inside Downing Street at the time, Lister agreed but seemed to say much of this was due to Dominic Cummings, Johnson’s chief adviser at the time. “He was not an easy man to deal with and that was a tension,” Lister said of Cummings, saying Johnson should have acted. “There was a personality clash that was constantly going on, and there was an atmosphere.” Asked about his own work with Cummings, Lister said: “We worked together. We had desks facing each other. I can’t say there was any close relationship.” Also in his evidence, Lister confirmed two anecdotes first described by Cummings, about what Lister termed “unfortunate” comments in meetings by Johnson. At an undetermined moment at the very start of the crisis, Lister said in his witness statement that Johnson proposed during a meeting being injected with Covid on TV “to demonstrate to the public that it did not pose a threat”. “I fully accept it’s a comment that should not have been made, but it was made at the heat of the moment,” Lister said when asked about it. Elsewhere in his witness statement, Lister confirmed that when a so-called circuit breaker brief lockdown was proposed amid fast-rising infection rates in September 2020, Johnson told a meeting he would prefer to “let the bodies pile high” instead. This was, Lister said, “an unfortunate turn of phrase”.