Rishi Sunak will be questioned about his actions during the Covid-19 pandemic when he appears before the hearing on Monday.

The Prime Minister was chancellor during the crisis and is likely to be questioned about the impact of his policies such as the Eat Out to Help Out scheme.

Government advisers referred to Mr Sunak as “Dr Death” during the pandemic, WhatsApp messages shown to the UK Covid-19 Inquiry have revealed, because of concerns about the impact of his push to keep economic activity going.

The correspondence between epidemiologist Professor John Edmunds and Professor Dame Angela McLean – now chief scientific adviser to the Government – took place during a meeting in September 2020.

Dame Angela messaged Prof Edmunds, referring to “Dr Death the Chancellor”, the inquiry was told.

Prof Edmunds told the inquiry the reference “could well be” about the Eat Out to Help Out scheme, which was devised by then-chancellor Mr Sunak and deployed a month earlier in a bid to kickstart the restaurant industry following lockdown.

The announcement that Mr Sunak will face a whole day of questioning on Monday came as former prime minister Boris Johnson began his second day of questioning.

Baroness Hallett’s inquiry has heard that scientists and then-health secretary Matt Hancock were left out of discussions around the Eat Out to Help Out scheme, which offered discounted meals in summer 2020 to help the hospitality trade after lockdown measures were lifted.

Mr Hancock told the inquiry he was not told about the scheme until the day it was announced and “argued very strongly” against the possibility of extending it at the end of August 2020.

The inquiry has also heard that former Government chief scientific adviser Professor Sir Patrick Vallance, England’s chief medical officer Professor Sir Chris Whitty and their former deputies Dame Angela and Professor Sir Jonathan Van-Tam were also not told about the scheme.

Sir Jonathan said: “I would have said ‘this is exactly encouraging what we’ve been trying to suppress and get on top of in the last few months’. So it didn’t feel sensible to me.”

Prof Edmunds said he did not want to blame Eat Out To Help Out for the second Covid-19 wave, but the “optics” around the scheme were “terrible”.

He said he understood the restaurant sector needed support, but that this “was not really just supporting them”.

“They could have just given them money,” he added. “This was a scheme to encourage people to take an epidemiological risk.”

In response to the comments, inquiry counsel Hugo Keith said: “To make it clear, there is very little or there’s weak epidemiological evidence to show that infections in the areas in which people took up the scheme went up significantly. Your point is at the optics of it.”

Prof Edmunds said advisers were measuring public behaviour in August and at the time there was a change.

He added: “I wouldn’t say it was Eat Out To Help Out, but it was contributing.”