Boris Johnson and his former adviser Dominic Cummings sent “disgusting and misogynistic” WhatsApp messages that will be released by the COVID inquiry next week, George Osborne has claimed.

The former Tory chancellor said he understands that some “pretty astonishing and frankly, shocking” messages will be made public when Mr Cummings gives evidence at the hearings at the end of the month.

Speaking on the 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”.

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Pressed for details by his co-host Ed Balls, he said he had to “be careful here because it’s a judicial inquiry”.

But he added: “From what I understand, there are some pretty staggering things that have been said on those WhatsApp messages by not just by Boris Johnson, but key advisers like Dominic Cummings, really, pretty disgusting language and misogynistic language.

“But I think that’s all I can say because I’ve already appeared once before the COVID inquiry and I don’t want to appear again before it.”

Mr Johnson and Mr Cummings have not commented on the claims.

A string of embarrassing messages have already been released to the inquiry, including how Mr Johnson described long COVID as “b*******” and that his wife, Carrie, had been described as “the real person in charge” by the head of the UK’s civil service.

Mr Cummings has said he is due to give evidence on October 31.

He was Mr Johnson’s closest aide when the pandemic hit, and the government was forced to defend him after he drove to County Durham beauty spot Barnard Castle during the first lockdown.

He left Downing Street in November 2020 following infighting in No 10 and has since become a fierce critic of the former prime minister, suggesting he was indecisive in the response to coronavirus.

The COVID inquiry began this summer and has so far heard evidence from Mr Osborne and ex-prime minister David Cameron – who were grilled on the impact of their austerity programme on the NHS and its ability to plan for a pandemic.

The first part of the inquiry looked at the UK’s resilience and preparedness for a pandemic while the second part, which started this month, focuses on “core decision making and political governance” and will also see Mr Johnson give evidence.

As part of the inquiry, key decision makers – including ministers, former ministers and senior civil servants – have been asked to disclose communications, including those through informal channels such as WhatsApp, Microsoft Teams or Signal.

Separately, it emerged this week that the “majority” of WhatsApp messages shared among Scottish Government officials during the pandemic may have been deleted.

Jamie Dawson KC – the lead counsel in the Scotland module of the inquiry – told the hearing on Thursday that “although WhatsApps appear to have been used to send messages relating to and surrounding key decisions by some members of Scottish Government, the majority of the messages have not been retained by witnesses”.

Mr Dawson went on to say there is a “lack of certainty” around what materials are held by the government and its officials, where it is held, and what can be recovered, and the inquiry has sought more information about the circumstances in which the messages were not retained.

The UK government was taken to court after it refused to hand over Mr Johnson’s messages to the inquiry, stating the messages were irrelevant.

However, the high court ruled against the cabinet office, stating it was up to Baroness Hallett, the chair of the inquiry, to decide whether the material was relevant or not.

Lady Hallett has said she is “very concerned about the difficulties” in obtaining the messages from the Scottish government, and she “will not hesitate” to use “statutory powers” at her disposal to obtain the relevant information.