The official public inquiry into the government’s handling of Covid threatened the Cabinet Office with criminal sanctions over its refusal to share Boris Johnson’s WhatsApp messages and diaries from during the crisis without heavy redactions. The inquiry issued a legal notice requesting Johnson’s unredacted WhatsApp communications, his official diaries from between January 2020 and February 2022, together with 24 notebooks, revealing for the first time the scale of notes taken by the former prime minister while in office. These included exchanges and group chats between senior government ministers, senior civil servants and their advisers during the Covid crisis, including the chief medical officer for England, Sir Chris Whitty, the then chief scientific adviser, Sir Patrick Vallance, and the former NHS chief Simon Stevens. They also include their messages with the former No 10 adviser Dominic Cummings and cabinet ministers at the time including Rishi Sunak, Liz Truss and the then deputy prime minister, Dominic Raab, the then health secretary, Matt Hancock, as well as the cabinet secretary, Simon Case. However, after receiving the legal order on 28 April this year, the Cabinet Office refused the request, which had been made under section 21 of the Inquiries Act 2005, two weeks later, contending it was unlawful, according to inquiry documents. Lady Hallett, the chair of the Covid inquiry, has now dismissed the Cabinet Office’s response, saying she believed the initial order was within the law. Failure to comply without reasonable excuse would be a criminal offence, punishable with a fine of up to £1,000 or imprisonment for a maximum of 51 weeks. Johnson has dropped the government-appointed lawyers representing him at the Covid inquiry after he was referred to police, the documents show. Allies suggested he had lost confidence in the Cabinet Office. However, in line with longstanding practice for former ministers, the taxpayer will still fund his new legal representation. Hallett, a former court of appeal judge, said she wanted to see messages even if it was not immediately obvious they were relevant to the investigation, as they could show whether ministers had dealt with pandemic issues inadequately because their attention had been elsewhere. She cited public concern over Johnson’s lack of focus on Covid in early 2020. She also highlighted “important” areas that the Cabinet Office had initially decided were “unambiguously irrelevant” to the inquiry, but on which she had recently received unredacted material. These included discussions between the former prime ministers and aides about the Metropolitan police’s enforcement of Covid regulations following the murder of Sarah Everard. Downing Street insisted the government was supplying “all relevant material” to the inquiry and had already provided more than 55,000 documents, 24 personal witness statements and eight corporate statements. It believed it had no duty to disclose “unambiguously irrelevant” material. The prime minister’s official spokesperson said: “We established the inquiry to ensure the actions of the state during the pandemic are examined as rigorously and candidly as possible to ensure we learn the right lessons for the future. The government remains committed to its obligations to the inquiry and in line with the law.” He added: “The principle in question here is around disclosure of materials which are clearly irrelevant to the work of the inquiry – for example WhatsApps which are personal in nature, of no relevance to the work of the inquiry, or relate to a wholly different area of policy. “It’s our position that the inquiry does not have the power to compel the government to disclose unambiguously irrelevant material, given the precedent that this would set and its potential adverse impact on policy formulation in the future.” In documents published on Wednesday on the inquiry’s website, Hallett said: “The entire contents of the documents that are required to be produced are of potential relevance to the lines of investigation that I am pursuing.” Hallett said the inquiry had requested potentially relevant WhatsApp materials from a large number of witnesses, including key decision-makers, senior civil servants and government advisers. She suggested that if the Cabinet Office regarded the request as unlawful, it should apply for judicial review. She suggested that the government had misunderstood the scope of the inquiry, adding: “I reject the contention that the notice was issued unlawfully. The application will therefore be dismissed.” Hallett, a crossbench peer, said the terms of the inquiry were of “great breadth” and she would “undertake a large number of extremely diverse lines” including “superficially unrelated” political matters that concerned ministers and officials at the time. “Such matters may acquire greater significance where it appears to me, or it is otherwise suggested, that a minister dealt with Covid-related issues inadequately because he or she was focusing (perhaps inappropriately) on other issues,” she wrote. “For similar reasons, I may also be required to investigate the personal commitments of ministers and other decision-makers during the time in question. There is, for example, well-established public concern as to the degree of attention given to the emergence of Covid-19 in early 2020 by the then prime minister.” Rivka Gottlieb, a spokesperson for Covid-19 Bereaved Families for Justice UK, said: “This inquiry needs to get to the facts if it is to learn lessons to help save lives in the next pandemic. “It’s outrageous that they think they can dictate to an independent inquiry which of Boris Johnson’s WhatsApp messages they can see. With the revelations that have come out about him breaking lockdown rules, you really do fear the worst about what they’re hiding.”