Downing Street has slapped down a Conservative MP who warned against the UK becoming a “public health socialist state”, after Chris Whitty suggested people cut down on pre-Christmas socialising.

Speaking at a Downing Street press conference on Wednesday alongside the prime minister, England’s chief medical officer urged the public: “Don’t mix with people you don’t have to.”

The comments intensified calls from the hospitality sector for financial aid to help them cope with plunging bookings.

Joy Morrissey, the MP for Beaconsfield and a parliamentary aide to the justice secretary, Dominic Raab, tweeted on Friday morning: “Perhaps the covid unelected public health spokesperson should defer to what our ELECTED members of parliament and the prime minister have decided.”

She added: “I know it’s difficult to remember but this is not how democracy works. This is not a public health socialist state.”

Boris Johnson’s official spokesperson said the prime minister did not agree with the view expressed by Morrissey. “Professor Whitty is a hugely respected and trusted public servant, who provides independent, evidence-based advice,” he said.

Morrissey replaced Dominic Grieve as Beaconsfield MP after the former attorney general was thrown out of the Conservative party for trying to block a no-deal Brexit.

She took down the tweet after less than half an hour but subsequently posted a more moderate version of the same message, saying she was “increasingly concerned” about “public health pronouncements made in the media”.

Labour called for Morrissey to apologise or be sacked from her role as Raab’s parliamentary private secretary.

In a letter to Raab, the shadow justice secretary, Steve Reed, said: “It is vital, especially during this pandemic, that our leading scientists have the freedom to give public health advice to the public and to offer their expertise without fear of reprisal. As the Omicron variant spreads rapidly through Britain, there must not be any sign of the government censoring or intimidating our leading scientific experts.”

Several other Conservative MPs have also reacted with anger to Whitty’s comments, which intensified calls from the hospitality sector for financial aid to help them cope with plunging bookings.

Johnson suffered his largest ever rebellion over Covid restrictions on Tuesday, with 100 Conservative MPs voting against the government’s plans for Covid passes.

In the House of Commons on Thursday, Steve Baker asked the Treasury minister John Glen: “What reassurance can he give me that when officials speak, particularly on podiums at press conferences, that they are staying within the bounds of the policy that ministers have decided?”

During the same debate, over financial support for businesses hit by the Omicron wave, the former public health minister Steve Brine said: “At a stroke the chief medical officer changed government policy and put this country, certainly hospitality, into effective lockdown.” He claimed: “Advisers are now running the show.”

Downing Street played down differences between Whitty and the prime minister’s stance, however. Johnson’s spokesperson said: “Both the prime minister and the [chief medical officer] were making the point that given the current infection rate, the prevalence of the variant, people should be cautious.”