Boris Johnson was facing mounting fury from within his own party on Saturday as anger grew over the partygate scandal engulfing his premiership.
Former allies were among those calling on the prime minister to stand down as MPs' inboxes filled with angry correspondence from constituents.
As Mr Johnson bunkered down in No 10 after another damaging week of revelations, ex-minister Tobias Ellwood was among those floating the prospect of a change at the top, saying Mr Johnson should "lead or step aside".
"We need leadership," Mr Ellwood, the chair of the Commons defence committee, told the BBC.
The prime minister and his allies have called on disgruntled Tory MPs to wait for an inquiry by civil servant Sue Gray to report on the matter, hoping that it will exonerate him.
But Andrew Bridgen, a staunch Brexiteer who backed Mr Johnson in the 2019 leadership election, said he did "not need to see what Sue Gray says to know that, for me, Boris Johnson has lost the moral authority to lead the country".
Asked about new reports that Downing Street staff regularly held "wine time Friday" with the PM's knowledge, the MP said: "It doesn't matter, quite honestly, if the prime minister was present or not present.
"Ultimately, he is responsible for what goes on in government, he is responsible for the culture in No 10, and what we're seeing is a culture where it is one rule for them and the rest of us do as we're told, and that's just not acceptable.
"I'm not sure that any apology is going to put that right."
Former children's minister Tim Loughton became the latest Tory MP to call for Mr Johnson to resign on Saturday night, saying that his position is "now untenable". The East Worthing and Shoreham MP, in a post on social media, said: "His resignation is the only way to bring this whole unfortunate episode to an end and I am working with colleagues to impress that view on Number 10.
“Obfuscation, prevarication and evasion have been the order of the day when clarity, honesty and contrition was what was needed and what the British people deserve.”
After The Independent revealed earlier this week that Mr Johnson was drawing up a list of officials to offer resignations to salvage his premiership, it has now been reported he is planning a series of populist announcements as part of 'Operation Red Meat'.
Among the proposals, Mr Johnson will announce a workplace "booze ban" within No 10, freeze the BBC licence fee for two years and give the military control of the effort to stop illegal Channel crossings, the Sunday Times reports.
A slew of polls in recent days have put the Tories at least 10 points behind Labour - with the latest Opinium poll on Saturday putting Labour ahead at 41 per cent - and Conservative MPs have reported being deluged with angry correspondence from constituents demanding Mr Johnson step down or be removed in light of the revelations.
But the prime minister has cancelled public appearances after a family member apparently tested positive for Covid, and has not been seen outside Downing Street in recent days.
The mechanism for removing Tory leaders means disgruntled MPs must reach a critical mass in the party. Under Tory rules, 15 per cent of all MPs must decide to write anonymous letters calling for a leadership contest – a threshold that has not yet been reached.
The letters are always anonymous so there is no solid way to tell how many have been sent to the committee’s chair. 54 are needed because there are 360 MPs in the current Tory parliamentary party, but just three MPs are confirmed to have written so far. Some estimates suggest there could privately be around a dozen letters with the committee.
The opposition also seized on the latest claims about lockdown social events in No 10, with Labour leader Keir Starmer using a speech in London on Saturday to blast the prime minister.
Speaking at the Fabian society conference, opposition leader Sir Keir told his audience: "We are witnessing the broken spectacle of a prime minister mired in deceit and deception, unable to lead.”
He said that while "the Tories bicker and fight each other on WhatsApp, I want to look to the future".
The opposition chief added: "The moral authority matters of course in relation to Covid, but we've got other massive challenges facing this country.
"We've got a prime minister who is absent - he is literally in hiding at the moment and unable to lead, so that's why I've concluded that he has got to go.
"And of course there is a party vantage in him going but actually it is now in the national interest that he goes, so it is very important now that the Tory Party does what it needs to do and gets rid of him."
And about the allegations of "wine-time-Friday", Sir Keir added: “It doesn’t matter whether the prime minister was present or not present – ultimately, he is responsible for what goes on in the government, he’s responsible for the culture in No 10 and what we’re seeing is a culture where there’s one rule for them and the rest of us do what we’re told.”
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