What will happen if Boris Johnson resigns?

In the House of Commons today, the Prime Minister will face MPs at noon as he battles to save his premiership.

It will be Boris Johnson's first public appearance since a leak on Monday of an email from his principal private secretary, Martin Reynolds, inviting Downing Street staff to the gathering in May 2020 to “make the most of the lovely weather”.

The disclosure triggered a new wave of public anger following the reports last year of parties in the run up to Christmas 2020, with Tory MPs openly warning Mr Johnson his position will be untenable if he has been shown to have lied.

Mr Johnson has refused to say if he was present at the May event, despite reports he and his fiancee (now wife), Carrie Symonds, were among around 30 people to attend at a time when such gatherings were banned.

The Prime Minister has said it is a matter for Sue Gray, the senior civil servant who is investigating a series of reported parties in Downing Street and elsewhere in Whitehall in the course of 2020 to determine what happened.

Backbencher Nigel Mills warned that any senior figure who willingly attended the event could not have a position where they were responsible for setting Covid-19 policy.

“It is utterly untenable, we have seen people resign for far less than that. If the Prime Minister knowingly attended a party, I can’t see how he can survive,” he told the BBC.

“I don’t think we need an inquiry to work out whether the Prime Minister was there. He knows whether he was there or not. Just come out and say what happened.

“If he was there he better try a hugely fulsome apology and see if the country will buy it but I’m not sure they will.”

His comments echoed the leader of the Scottish Tories, Douglas Ross, who called for the Prime Minister to come clean about whether he attended the event and again warned that Mr Johnson could not carry on in No 10 if he was found to have misled Parliament.

With the public mood turning increasingly angry, two snap polls found a majority now believed Mr Johnson should stand down as Prime Minister.

A Savanta ComRes study found 66% of British adults thought he should quit, with 24% saying he should stay, while a YouGov survey for Sky News found 56% believed he should go, with 27% saying he should remain.

Meanwhile, Scotland Yard has said it is in contact with the Cabinet Office about the latest allegation.

If a Prime Minister announces their resignation, there are a number of outcomes.

What will happen if the PM resigns?

Traditionally, if a Prime Minister loses a general election they will offer their resignation to the monarch.

The monarch will then invite the party with the largest majority to form a new government in their name.

However, this process would be different if Boris Johnson opts to resign while his government is still in power.

Should this occur, a leadership contest is triggered, in which fellow members of the government will make their case to be the new leader of the party.

In the meantime, as a decision is made, the Deputy Prime Minister Dominic Raab would take on the role temporarily.

Boris Johnson would offer his resignation to the Queen when the outcome of the leadership contest has been decided, prompting the monarch to appoint the new leader of the party as prime minister.

The new prime minster can then choose to hold a general election, as Boris Johnson did when he took over from Theresa May in 2019, however they are not required to do so.

Who has previously resigned as Prime Minister?

Tony Blair announced his resignation on May 10 2007, triggering a Labour leadership contest which was won by Gordon Brown.

Brown achieved 313 nominations, beating his only opponent, John McDonnell, to become prime minister of the UK on June 27 2007.

Similarly, David Cameron resigned on June 24 following the outcome of the Brexit referendum and Theresa May assumed the position as leader of the Conservative party.

Another leadership contest was also triggered after May resigned on June 7 2019.

Boris Johnson defeated his opponent Jeremy Hunt in the leadership contest and was elected Conservative leader on 23 July 2019.