Chief medical officer Sir Chris Whitty will give evidence to the Covid-19 Inquiry later, in a highly anticipated appearance.

The evidence session by Sir Chris, who became one of the most recognisable figures in the country during the pandemic, is expected to last for the whole of Tuesday and could even extend into Wednesday.

His appearance comes a day after former chief scientific adviser Sir Patrick Vallance, a close colleague who frequently appeared alongside him at coronavirus-era press conferences, offered his insights into former prime minister Boris Johnson and ministers’ handling of the pandemic.

Chancellor Rishi Sunak visits Scotland
Then-chancellor Rishi Sunak launched Eat Out To Help Out in August 2020 (PA)

Diary entries by Sir Patrick have so far offered extraordinary insights into his view of Mr Johnson, Rishi Sunak and the decisions taken by politicians as the crisis unfolded.

Lady Hallett’s inquiry heard on Monday that Mr Johnson was “bamboozled” by the graphs and data presented to him during the pandemic and was sometimes a “broken” man.

The inquiry heard how Mr Johnson sometimes struggled to retain scientific information, was “clutching at straws” and at one point queried whether Covid was spreading “because of the great libertarian nation we are”.

Sir Patrick’s diaries also suggested that Mr Sunak, then chancellor, thought it was “okay” to “just let people die”.

Sir Chris Whitty, Sir Patrick Vallance and then prime minister Boris Johnson leaving 10 Downing Street, London, ahead of a Covid-19 media briefing (Dan Kitwood/PA)

Laura Trott, the Chief Secretary to the Treasury, did not deny that Mr Sunak had made such remarks as she said it was up to the inquiry to establish that.

It “will be for him to talk about these individual things” when he appears before the inquiry, she said on Tuesday.

Pointing to the “vital” furlough scheme, Ms Trott said Mr Sunak “provided a great amount of leadership” during the pandemic.

She also declined to comment on whether Mr Sunak’s Eat Out To Help Out scheme was a good idea.

“That’s exactly what we’ve got the independent inquiry to look at,” the Cabinet minister said.

The initiative, launched in August 2020 to kickstart restaurants and eateries post-lockdown, faced criticism again on Monday.

The inquiry has already heard that Sir Chris privately referred to it as “eat out to help out the virus”, and he is likely to face questions about the initiative later.

His former deputy, Sir Jonathan Van-Tam, will give evidence later in the week.