The COVID inquiry has issued a legal notice to the Cabinet Office for not handing over the full contents of Boris Johnson’s messages.
The Cabinet Office tried to object to handing over the communications but was overruled by Baroness Hallett, the chair of the COVID inquiry.
But the inquiry chair has ordered that the release of unredacted WhatsApp messages and diary entries from the former prime minister.
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The order was first made last month, but the Cabinet Office appealed it.
Downing Street insisted the government was supplying “all relevant material” to the inquiry.
The Cabinet Office has already provided more than 55,000 documents, 24 personal witness statements and eight corporate statements to the inquiry.
But the government believes it has no duty to disclose “unambiguously irrelevant” material, according to the Cabinet Office in its initial objection.
Lady Hallett disagrees, and under the Inquiries Act 2005 has the final word.
She said in her ruling that all these documents “contain information that is potentially relevant” to how decisions were made during the pandemic.
Mr Johnson wrote to the inquiry claiming that he was not the one to blame for the redactions, and that the order “may directly and/or indirectly suggest that I have failed to provide documents to the Inquiry”.
He added: “Any such suggestion or implication would be unfair and untrue.”
Writing in a letter dated 24 May, he asked for at least a 48-hour to delay the publication of the order, so he could seek legal advice.
He also revealed that he is currently changing his legal team.
The inquiry did not grant this delay and published the order the same day – although they published the letter from Mr Johnson alongside their announcement today.