Boris Johnson's future is hanging in the balance as cabinet ministers pleaded with Tory MPs to wait for the findings of an official investigation into Downing Street parties before calling for him to quit.

The UK Prime Minister apologised in the Commons yesterday for attending a "bring your own booze" party in the Downing Street garden in May 2020, during Britain's first coronavirus lockdown. However, he insisted he believed it was a work event and could "technically" have been within the rules.

Mr Johnson's confirmation that he was at the event led to four Tory MPs publicly calling for him to quit, with more privately voicing concerns about his leadership.

The prime minister pulled out of a planned visit to a vaccination centre in Lancashire earlier today where he would have faced questions from the media about his actions, because a family member tested positive for coronavirus.

Secretary of State for Northern Ireland Brandon Lewis urged people to wait for the outcome of an inquiry by senior civil servant Sue Gray into alleged lockdown-busting parties in No 10 and Whitehall before making judgements on Mr Johnson's future.

"The prime minister has outlined that he doesn't believe that he has done anything outside the rules. If you look at what the investigation finds, people will be able to take their own view of that at the time," he said.

Cabinet ministers rallied round to defend Mr Johnson, but the late interventions of Foreign Secretary Liz Truss and Chancellor Rishi Sunak - both tipped as potential successors - did little to instil confidence in his future.

While Mr Johnson endured a difficult session of Prime Minister's Questions yesterday, Mr Sunak had notably spent the day away from London on a visit in Devon.

But Northern Ireland Secretary Mr Lewis told Sky News: "I have seen Rishi working with the prime minister. They work absolutely hand-in-hand. I know that Rishi has got support for the prime minister."

Mr Lewis insisted Mr Johnson was the right person to be prime minister and "I think we will be able to go forward and win a general election".

Scottish Conservative leader Douglas Ross was among those urging Mr Johnson to step down

Mr Johnson faced open revolt from one wing of his party, as Scottish Conservative leader Douglas Ross urged him to quit, with almost all Tory MSPs supporting the call.

Mr Ross was dismissed as a "lightweight figure" by Commons Leader Jacob Rees-Mogg following his intervention.

In Westminster, three other Tory MPs said Mr Johnson should go - Roger Gale, former minister Caroline Nokes and chairman of the Public Affairs and Constitutional Affairs Committee William Wragg.

Read more:
Boris Johnson badly damaged by 'partygate' affair

In the Commons yesterday, Mr Johnson said he recognised "with hindsight I should have sent everyone back inside" instead of spending 25 minutes in the No 10 garden thanking staff for their work on 20 May 2020.

Downing Street insisted he had not been sent an email from his principal private secretary, Martin Reynolds, encouraging colleagues to go to the garden for "socially distanced drinks" to "make the most of this lovely weather" - and urging them to "bring your own booze".

Protestors in Parliament Square in London earlier this week amid public anger over a 'bring your own booze' party in the garden behind No 10 during England's first lockdown in May 2020

Mr Johnson told MPs "there were things we simply did not get right and I must take responsibility".

The UK Labour Party's shadow communities secretary Lisa Nandy said that relatives of those who died during the pandemic are "appalled, horrified and retraumatised" by the events, asking how senior ministers could have been telling the country what to do during the lockdown "and yet they weren't doing it themselves".

Meanwhile, Mr Johnson's government suffered another blow as one of its most effective communicators during the pandemic announced his departure.

Professor Jonathan Van-Tam is to leave his role as England's deputy chief medical officer at the end of March. He is to take up a new role as the Pro-Vice Chancellor for the faculty of medicine and health sciences at University of Nottingham.