The former high court judge Heather Hallett is chairing the independent public inquiry into the Covid-19 pandemic. It has heard from key scientists, who have criticised the lockdowns as a “failure of public health policy” and claimed they were “used as human shields” by ministers. This week, Dominic Cummings and other members of Boris Johnson’s inner circle are due to give evidence. On Monday, Martin Reynolds, a former adviser to Boris Johnson who was nicknamed Party Marty after an email showed he had invited more than 100 Downing Street staff to a “bring your own booze” event during the first lockdown, appeared at the inquiry. Here is what you may have missed from the inquiry so far: 1. A ‘terrible, tragic joke’ In messages discussing enforcing another lockdown in the autumn, Simon Case, who had been permanent secretary at 10 Downing Street and was appointed as head of the civil service in September 2020, warned that the government did not have the “credibility” to impose lockdowns after ministers repeatedly flip-flopped on what to do. “We look like a terrible, tragic joke. If we were going hard, that decision was needed weeks ago. I cannot cope with this.” In a WhatsApp group chat with Cummings and the former No 10 communications director Lee Cain, Case said ministers’ decisions appeared to be driven by “whatever Carrie [Johnson’s wife] cares about”. 2. The WhatsApp messages we won’t see The government fought a long legal battle to prevent the full release of WhatsApp and Signal messages to the inquiry, but the high court ruled in July that it must hand over two years’ worth of messages from ministers and nearly 40 other senior figures and advisers. However, neither Johnson nor Rishi Sunak can provide months’ worth of messages sent during the height of the crisis. The prime minister says he does “not have access” to months of messages from when he was chancellor because he changed phones frequently and did not back up the chat. The missing period includes when he launched the controversial “eat out to help out” scheme designed to encourage people to go out to restaurants. It cost £850m and was subsequently linked to a jump in Covid cases. No epidemiologist was officially consulted on the scheme beforehand. Johnson has told the inquiry he is unable to access messages between 31 January and 7 June 2020 – which covers the first three months of the pandemic – despite the phone he was using then being in action until the following spring. “The technical team [helping him access the phone] has been unable to determine the cause of this,” he said in a statement to the inquiry. 3. Sir Patrick Vallance’s ‘brain dump’ diary While ministers and their advisers were busy messaging each other at all times of the day and night in more than 250 WhatsApp groups, the then chief scientific adviser, Sir Patrick Vallance, was writing a deeply frank “brain dump” diary before turning in each night. In entries in his “evening notes”, he said scientists were “used as human shields” by ministers and officials, and he accused No 10 of “cherrypicking” from scientific advice in order to publicly claim they were “following the science” when announcing potentially unpopular decisions. While Vallance handed over the diaries to the inquiry, they have not been shown on the big screen at Dorland House or on the livestreamed coverage. Only specific extracts have been read out by lawyers. Victims’ families – and the media – are now calling on Lady Hallet to rule that his diary entries should be displayed in context like the other evidence. A lawyer representing Vallance said they should not be, as the notes were written only as a “brain dump” to protect his mental health. “A form of release which helped him focus on the challenges of the next day rather than dwelling on the events of the past.” 4. What might Boris Johnson be asked? The inquiry has sent 150 questions to Johnson in advance, so we have a good idea of how his two-day appearance will play out. One asks: “In or around autumn 2020, did you state that you would rather ‘let the bodies pile high’ than order another lockdown, or words to that effect?” Another is: “Why did you not attend any Cobra meetings in relation to Covid-19 before 2 March 2020, given the seriousness of the emergency?” And one that could be troublesome for Johnson and Sunak asks: “What discussions did you have with the then chancellor about the ‘eat out to help’ out scheme before its implementation in August 2020?”