Dominic Cummings, Boris Johnson
Former Prime Minister Boris Johnson announced today that he is joining GB News as a presenter. AFP News/Daniel LEAL

Boris Johnson and his former adviser Dominic Cummings sent "sexist" WhatsApp messages during the Covid pandemic, the ex-chancellor of the exchequer has claimed.

George Osborne, who served in the Cabinet between 2010 and 2017, described some "pretty astonishing and frankly, shocking" messages that will be released by the COVID inquiry next week.

The independent public inquiry is tasked with assessing the United Kingdom's response to, and the impact of, the COVID-19 pandemic, and to learn lessons for the future.

As part of the inquiry, ministers were asked to provide access to their WhatsApp correspondence during this period.

Speaking on his 'Political Currency podcast', Mr Osborne said the messages "will show people just what a complete nightmare it was to work in Downing Street during the pandemic" and "potentially some things that are going to cause some real problems for individuals who were in charge at the time".

Then pressed for details by his co-host Ed Balls, he said he had to "be careful here because it's a judicial inquiry".

Cummings and Johnson declined to comment on Osborne's remarks.

Former Prime Minister Johnson was forced to resign from his position last year following the 'Partygate' controversy.

Several photos emerged of him drinking at a Downing Street party during the lockdown in 2020. He came under fire for breaking COVID-19 protocols and was eventually forced to quit.

Dominic Cummings also left Downing Street – in November 2020 – after internal battles over his role as Boris Johnson's chief adviser.

Next Tuesday, Cummings is due to give evidence at the public inquiry, while the former prime minister is expected to give evidence next month.

Current Prime Minister Rishi Sunak also served as chancellor during the pandemic, but he has reportedly failed to provide his WhatsApp messages to the inquiry committee.

He claims he does not have the messages from the time because he had to change his mobile several times and failed to back them up.

Several embarrassing messages have already been released by the inquiry.

Simon Case, the cabinet secretary, described Johnson's wife Carrie as "the real person in charge" and said the government looked like a "terrible, tragic joke" in one set of messages.

Case, who became cabinet secretary in September 2020 and had been permanent secretary in No 10, made the comments in a group that included Lee Cain, the head of communications, and Cummings.

Earlier this year, Johnson's former health secretary, Matt Hancock, became the centre of a massive controversy after it came to light that he allegedly failed to follow advice on COVID-19 testing.

Thousands of WhatsApp messages were leaked to the Daily Telegraph, showing that Hancock did not heed the advice given by England's Chief Medical Officer, Chris Whitty, about testing everyone who goes into care homes in April 2020.

Instead of testing all the people going into care homes, Hancock decided to make it mandatory to test only those entering care homes from hospitals.

Testing for everyone was made mandatory only in August 2020, by then the situation had already escalated.

Ex-PM Johnson has also been under fire for his handling of the pandemic.

Earlier this year, a parliament committee ruled that Johnson deliberately lied to MPs about lockdown-breaking parties during the Covid pandemic that would have seen him face a 90-day suspension had he not already quit as a lawmaker.

The Privileges Committee, which probes breaches of House of Commons rules, concluded that Johnson was guilty of "repeated contempt (of parliament) and seeking to undermine the parliamentary process".

"The contempt was all the more serious because it was committed by the prime minister, the most senior member of the government," they stated in a damning 106-page report.

The ex-Prime Minister avoided having to face his peers – and the humiliation of potentially having to run for re-election in his constituency – by resigning as an MP just days before the report was released.