A senior UK Government civil servant has admitted to setting WhatsApp messages to "disappear" in a chat group used during the pandemic.

Martin Reynolds, who was Boris Johnson's principal private secretary until 2022, told the UK Covid inquiry that he had turned on a "disappearing message function" on a group chat entitled "PM Updates" on 15 April 2021.

The function means that messages are automatically erased.

Mr Reynolds told the inquiry that he "cannot recall exactly why I did so", adding: "It could, for example, have been because I was worried of someone screenshotting or using some of the exchanges and leaking them."

A Downing Street spokesman said the use of disappearing WhatsApp messages is permitted as civil servants and ministerial private offices are required to record and log official decisions for the official record.

READ MORE: Reports suggest Sturgeon and Yousaf deleted WhatsApp messages 

It comes amid a row over claims that the UK Covid inquiry has been unable to obtain WhatsApp message records from dozens of Scottish Government ministers and officials covering pandemic-related exchanges.

WhatsApp messages disclosed to the UK inquiry by UK Government ministers and officials have already painted a picture of dysfunction and despair at the heart of Number 10 as the Covid crisis unfolded.

The Herald: The UK Covid inquiry heard how Boris Johnson 'blew hot and cold' on Covid restrictionsThe UK Covid inquiry heard how Boris Johnson 'blew hot and cold' on Covid restrictions (Image: PA)

One exchange highlighted during proceedings today, between Boris Johnson's then-chief of staff Dominic Cummings and Cabinet Secretary, Simon Case - the head of the civil service - revealed Mr Case's poor opinion of the then-Prime Minister, stating: "He [Johnson] cannot lead and we cannot support him... Government isn't actually that hard, but this guy is really making it impossible."

Mr Case also accused the PM of changing "strategic direction every day", and said the government looked like a "tragic joke".

The messages were sent in September 2020.

Another WhatsApp exchange revealed that the UK Government's chief scientific advisor, Sir Patrick Vallance, considered the PM "weak and indecisive".

Lee Cain - Boris Johnson's communications director during the pandemic - had been due to give evidence today but will instead appear tomorrow.

A WhatsApp conversation between Mr Cain and Mr Reynolds in June 2020, led in evidence at the inquiry, shows the pair discussing how they could host a leaving party for a member of staff given Covid rules on large gatherings.

Mr Cain described it as a "a substantial comms risk".

Mr Reynolds previously hit the headlines after leaked emails revealed that he had encouraged people to "bring their own booze" to a Downing Street get-together at the height of what is now known as 'Partygate'.

Giving evidence to the UK Covid inquiry, Mr Reynolds apologised, adding that these events had been "deeply damaging to trust in the government and damaging to public compliance".

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Hugo Keith KC - lead counsel for the inquiry - said there was a "great deal of material" from WhatsApp messages and diary entries indicating that when Mr Johnson returned to work after a life-threatening brush with Covid he "oscillated in terms of what should be done" and "wondered whether he should be regarded as the 'mayor in the Jaws film' - shutting the beaches".

Mr Reynolds said: "I think it's fair to say the Prime Minister did, as it were, blow hot and cold on some issues."

The Herald: Dominic CummingsDominic Cummings (Image: PA)

Mr Reynolds was asked about a report he and deputy cabinet secretary Helen MacNamara helped write in May 2020, amid concerns about "discipline", "macho behaviour" and "misogyny" during government Covid meetings.

Mr Keith said: "The report showed, did it not, dysfunctionality, lack of discipline, chaos and a significant degree of misogyny?"

Mr Reynolds responded: "I agree."

Mr Keith continued: "Women were talked over. People shouted at each other. There were too many people in meetings. Did you talk the Prime Minister through this report?"

"Yes I believe I did," Mr Reynolds responded.

READ MORE: UK Covid inquiry - what have we learned so far? 

The inquiry also heard how - in notebook entries dated May 25 2020 - Sir Patrick Vallance described Dominic Cummings' infamous lockdown trip to Barnard Castle lockdown trip as a "fiasco" and something that was "clearly against the rules".

Appearing to refer to an easing of lockdown, the note continues: "PM seems very bullish and wants to have everything released sooner and more extremely than we would.

"Wants to divert from the DC [Dominic Cummings] fiasco...All very worrying. Cabinet all upbeat and 'breezy confidence' - incredibly alarming."