Catherine Haddon from the Institute for Government think tank has told the BBC she expects the atmosphere in Westminster to be "febrile" tomorrow.

As many people would probably expect after today's shenanigans, she said the PM can expect "a really, really difficult day".

Although she wasn't sure whether there would likely be more resignations, Haddon said there would certainly be "more awkwardness".

"It will certainly be more people publishing letters and probably more of an idea of an eventual timetable for a vote of confidence," she said.

"It's going to be a febrile day."

Andrew Mitchell, a former Conservative chief whip, has compared Boris Johnson to Rasputin, the mystic who was close to Russia's imperial family.

The Conservative MP told BBC Newsnight it was "over" for the prime minister.

"This is an abnormal prime minister - brilliantly charismatic, very funny, very amusing, big, big character, but I'm afraid he has neither the character, nor the temperament to be our prime minister."

The BBC's deputy political editor Vicki Young tells BBC Radio 4's World Tonight some ministers are "still unhappy" and a couple of junior ministers she has spoken to tonight have not yet decided whether they're going to stay.

"So this is not necessarily the end of it."

Image source, PA Media

The newly appointed Steve Barclay has said it was "an honour" to take up the role of health secretary.

"Our NHS and social care staff have showed us time and again - throughout the pandemic and beyond - what it means to work with compassion and dedication to transform lives," he said.

"This government is investing more than ever before in our NHS and care services to beat the Covid backlogs, recruit 50,000 more nurses, reform social care and ensure patients across the country can access the care they need."

The PM won a vote of confidence in his leadership last month. Under the current rules of the 1922 committee, which organises Tory leadership contests, another challenge can't happen for 12 months.

However, MPs could still consider options to try to remove him.

Change the rules: There has been speculation the rules could be changed, so that Conservative MPs can hold another vote in Johnson's leadership sooner.

When asked about it, Sir Graham Brady MP, the chairman the 1922 Committee, said "technically, it's possible".

A vote is expected next week to re-elect members of the 1922 and some Tory backbenchers are expected to run on the basis that they would change the rules.

Cabinet pressure: Rishi Sunak and Sajid Javid believe their resignations are necessary to force Johnson to resign.

Boris Johnson still has his foreign secretary, home secretary, defence secretary and business secretary, but further resignations could pile on more pressure.

A far less likely route would be for the Cabinet to go the Queen and declare they don't have confidence in the PM.

Parliamentary motion of no confidence: A ballot where all MPs - not just Conservatives - get to vote has been proposed by Liberal Democrat leader Sir Ed Davey.

But the government would need to agree to make time in Parliament to hold such a vote and it would need to be brought by Labour.

Solicitor General Alex Chalk has just resigned. That role is a junior minister under the attorney general.

He said it was "with great sadness" he was quitting the post but added he could not "defend the indefensible".

"The cumulative effect of the Owen Paterson debacle, Partygate and now the handling of the former deputy chief whip's resignation, is that public confidence in the ability of Number 10 to uphold the standards of candour expected of a British government has irretrievably broken down. I regret that I share that judgement."

Chris Mason
Political editor

There was the whiff of panic hanging over it all. The prime minister's team had invited me in for a last-minute interview with Boris Johnson.

Five o'clock this evening, in his Commons office.

The mementoes of a political career are scattered around: an Olympic flag; a mocked-up plastic bus stop - with his name written on it as the destination; a framed newspaper front page marking a moment of victory.

But was this the moment that marked his defeat?

The prime minister had decided he had to confront the awkward truth that the people who spoke on his behalf hadn't been telling the truth, for days on end.

As I left, one of his most loyal ministers was heading the other way up the stairwell.

Others from Team Boris - those who originally championed him as a prospective Conservative leader - were summoned too.

Already it was obvious he was in peril. And then, for him, it got a whole lot worse.

His Health Secretary, Sajid Javid, walked. Walking matters, but words matter too.

"The British people rightly expect integrity from their government," he said.

The now former chancellor, Rishi Sunak, went further: the public expects the government to conduct itself "properly, competently and seriously".

The man who sat alongside the prime minister this morning saying the government is none of those things.

You can read Chris Mason's full analysis here.

Well, quite a lot in the space of a few hours. Here's a recap of the main developments:

• Boris Johnson has had to appoint a new chancellor - Nadhim Zahawi - and new health secretary - Steve Barclay

• This followed the dramatic resignations of Rishi Sunak and Sajid Javid within minutes of each other
• Earlier in the evening, the PM apologised for appointing a Tory MP to his government who had faced allegations of sexual misconduct
• Sunak said the public expected "government to be conducted properly, competently and seriously"
• Javid said he had "lost confidence" in Boris Johnson
• There followed the resignation of Conservative Party Vice-Chairman Bim Afolami, which he did live on TV
• A number of parliamentary aides have also quit

Branwen Jeffreys
Education Editor

Image source, Getty Images

Navigating this year's exam results in England will be one of the first big challenges for the new Education Secretary Michelle Donelan, who is stepping up from her post as Universities minister.

Grades in A-levels and GCSEs overall will bump down half way back to 2019 levels, and for the most competitive courses universities are being careful with their offers of places.

The first students to complete the new flagship T-Levels will also get their results.

Bringing in the rest of these technical qualifications successfully is a test of promises to level up vocational learning.

Two years of disrupted schooling have left some children further behind, and so many will be watching to see if the promised tutoring makes a difference.

On top of that, two draft laws have to get through parliament - freedom of speech at universities and the schools bill. It's a big brief to step into.

Nadhim Zahawi entered Downing Street as education secretary and left as Chancellor of the Exchequer.

The new appointment follows the resignation of Rishi Sunak, who stepped down from the role after Boris Johnson apologised for appointing Chris Pincher - who is facing sexual misconduct allegations - as deputy chief whip.

It is the second most important position in cabinet, after the prime minister - and means Zahawi will be responsible for the UK's finances.

In the past, Zahawi has expressed traditionally conservative views on the economy - including the need to keep the budget balanced and the deficit down.

More recently he's been a strong supporter of Sunak's approach - praising his predecessor's package to help families with the cost of living crisis in March this year.

In response to record inflation levels, Zahawi told LBC News in March that the only way to respond was by growing the economy as much as possible.

Theo Clarke, the prime minister's trade envoy to Kenya, has just resigned.

After a dramatic day at Westminster involving the resignations from the cabinet of Chancellor Rishi Sunak and Health Secretary Sajid Javid, BBC political editor Chris Mason assesses where this leaves Boris Johnson's government in the latest BBC Newscast.

In light of today's developments - from resignations to new appointments - YouGov carried out a snap poll, external, which suggests 69% of Britons say Boris Johnson should resign as prime minister.

Meanwhile, 54% of those who voted for Johnson in 2019 want him to resign.

But a high proportion of people, 68% of those who took part on the snap poll, said they think Johnson "definitely" or "probably" won't resign.

Iain Watson
Political correspondent

Assuming the PM digs in, then next week’s elections to the backbench 1922 committee are likely to be crucial.

If MPs standing on a platform of changing the leadership rules form a majority, it’s a moment of jeopardy for Boris Johnson.

While it had been anticipated that the rules could be changed to allow a further ‘no confidence’ vote within a year, it had been assumed that this might not take place until the autumn - after the Privileges Committee pronounces on whether the PM had deliberately misled parliament.

But there is now some talk of calling a confidence vote within 24 hours of the rules changing.

If Boris Johnson were defeated, then nominations would be open for a new leader, with MPs potentially whittling the candidates down to the final two before the summer recess.

Of course Westminster is, of course, nothing if not a hotbed of speculation.

And Boris Johnson has, Houdini-like, escaped from tight political spots before.

Though, ultimately, it didn’t end well for the escapologist.

Iain Watson
Political correspondent

One of the PM's allies claim Sunak and Javid had tried to 'tap up' support from other cabinet ministers unsuccessfully.

But some of the Boris Johnson's Conservative critics – including still-serving ministers – think he is holed beneath the water line.

If - and I stress If - Johnson's premiership does go under, how might it happen?

The first possibility – which may be wishful thinking on behalf of some rebels – is that more high level resignations follow in the coming days.

While remaining publicly loyal, it’s possible that some ministers will privately ask the PM to consider his position.

If he refuses to do so, this could provoke some further departures, with one minister telling me they’d go if the PM tries to stay on until the summer recess.

And some leadership hopefuls might just get nervous that Rishi Sunak will make all the running if they don’t at some point distance themselves from Number 10 too.

No 10 has also confirmed that Steve Barclay will be replacing Sajid Javid, becoming the new secretary of state for health and social care.

And Michelle Donelan is the new secretary of education, replacing Nadhim Zahawi's old role.

This as Nadhim Zahawi becomes the new chancellor.

The education secretary has been chosen to replace Rishi Sunak, who quit earlier this evening.

Faisal Islam
BBC Economics Editor

Rishi Sunak was a crisis chancellor. He spent his time expanding the state, spending and levels of taxation, against his instincts to deal with the pandemic and Ukraine crisis.

He was however keen to draw a line under that support, even as it had made him popular.

Sunak rolled back the pandemic increase in universal credit. The energy crisis was not a "whatever it takes" moment.

At Number 10, their instincts were to borrow more, tax less and support households more.

The key line in all the resignation letters released tonight is that the chancellor felt his approach to the economy was "fundamentally too different" to that of Boris Johnson.

Without Sunak, and with a new chancellor, the PM will find it easier to tax less, perhaps spend more and so borrow more.

But that comes against increasing market concern about the UK’s growing trading deficit, a slump in sterling, and fears of recession.

It is exactly the sort of time a government might rely on having an Iron Chancellor, who can rein in his or her crisis-afflicted neighbour.

But this may not be the likely direction of travel in Downing Street.

Here's our running tally...

Who has left cabinet?

• Health Secretary Sajid Javid
• Chancellor Rishi Sunak

Who else in government has resigned?

MPs who are Parliamentary aides to Cabinet ministers

• Jonathan Gullis
• Saqib Bhatti
• Nicola Richards
• Virginia Crosbie

Others

• Bim Afolami (Tory vice-chair)

Who is staying in cabinet?

• Deputy Prime Minister/Justice Secretary Dominic Raab
• Home Secretary Priti Patel
• Foreign Secretary Liz Truss
• Defence Secretary Ben Wallace
• Levelling Up Secretary Michael Gove
• Business Secretary Kwasi Kwarteng
• Northern Ireland Secretary Brandon Lewis
• Scottish Secretary Alister Jack
• Leader of the Commons Mark Spencer
• Environment Secretary George Eustice
• Transport Secretary Grant Shapps
• Work and Pensions Secretary Therese Coffey
• Culture Secretary Nadine Dorries
• Brexit Opportunities Minister Jacob Rees-Mogg

Image source, Twitter

Rishi Sunak and Sajid Javid - who quit the cabinet within minutes of each other in protest at Boris Johnson's leadership - are friends who share similar backgrounds.

They both rose from modest beginnings to make a fortune in investment banking, before entering politics.

And they share a love of Star Wars.

When Javid resigned as chancellor in February 2020, he tweeted his successor: "The Force is strong in young Sunak."

For his part, Mr Sunak once hailed his former boss as his "Jedi Master".

The pair are also ideological soulmates, seeing themselves as being part of the low tax and spending Thatcherite wing of the Conservative Party.

So, as they step outside the cabinet, will the force remain with them?

BBC News political reporter Brian Wheeler looks at the bond between two of the Conservative Party's biggest names.