Image source, Reuters

Boris Johnson has announced he will not stand for the Tory leadership.

He is saying that despite having the support of the MPs required to run, he had come to the conclusion "this would simply not be the right thing to do" as "you can't govern effectively unless you have a united party in Parliament".

He says he had the backing of 102 MPs, however the BBC is unable to verify this figure as only 57 MPs had publicly declared their support.

Here's an at-a-glance guide to where we are on the eve of deadline day for Tory leadership candidates to gain the support of 100 MPs.

• Rishi Sunak officially declared he is running for Tory leader and prime minister. He pledged to fix the economy, unite the Conservative party and "deliver for our country"
• Penny Mordaunt, who was first to announce herself as an official candidate, told the BBC she is "in it to win it"
• Although Boris Johnson has not formally declared he'll be running, his allies say he has the backing of 100 MPs and will be on the ballot tomorrow - but we have not been able to verify this number
• Candidates have until Monday at 14:00 BST to gather the support of 100 MPs

You can stay up to date with who is backing whom here, where we are keeping our own tally. So far 228 of 357 Tory MPs have gone public with their support:

Rishi Sunak - 147 MPs

Boris Johnson - 57 MPs

Penny Mordaunt - 24 MPs

Nick Eardley
Chief political correspondent

We could have a new prime minister tomorrow. We'll definitely have one by this time next week.

Many eyes tonight are on whether Boris Johnson stands. At the moment, Rishi Sunak is the only person we know for sure has the numbers.

In the WhatsApp group for MPs supporting Mr Johnson, the former chief whip Chris Heaton Harris has said tonight that they have verified their backers and completed the paperwork to get on the ballot tomorrow.

Mr Heaton Harris has said to Johnson backers that it's "very good news".

The Sun reported the message earlier this evening - and sources have confirmed it to the BBC.

What does this mean? Well we still don't have a list of 100 names backing Mr Johnson, so we can't be certain.

But if he does have 100 verified backers - it would mean Mr Johnson can get on the ballot of MPs tomorrow. I've spoken to people who have been on calls with him today and they're convinced he will stand.

But until it's confirmed - who'd say for certain? I've spoken with other MPs who just don't believe the former PM has the numbers. One source close to another campaign reckons Team Johnson are panicking tonight and trying to shore up their backers.

The BBC's latest tally of public backers is 57.

We all know that Westminster is an unpredictable place. Watch this space.

As there's so much going on, our political editor, Chris Mason and political correspondent, Alex Forsyth, have got together with Newscast host Adam Fleming, to record a special episode tonight.

How does the leadership race work?

How much support has each candidate got?

And what will happen this week?

You can listen to the full episode on BBC Sounds.

We're keeping a close eye on the number of public backings for the three people MPs say they want to become Britain's next prime minister.

Rishi Sunak and Penny Mordaunt have declared themselves in the running but Boris Johnson is yet to say whether or not he will stand.

The threshold to be on the ballot is the backing of 100 MPs.

However, if one of the candidates has the support of 155 MPs then it will no longer be mathematically possible for two other candidates to continue in the leadership race.

That's because there are a total of 357 Conservative MPs in Parliament.

The candidates cannot nominate themselves, so taking away the three potential leaders leaves 354. And take away 155 from 354 leaves 199.

According to the BBC's research, Rishi Sunak is the closest to gather the backing of 155 MPs. As things stand, 147 MPs have publicly said they'll endorse Sunak as the next leader and PM.

Johnson has the backing of 57 MPs and Mordaunt has 24.

Helen Catt
Political correspondent

This may be an internal contest but, as with any other election, the 1922 Executive doesn't just take a candidate's word for it that they have 100 backers.

The process isn’t public, or published, but here’s my best understanding of how it works from speaking to people who are involved in various ways.

Two Conservative MPs have to act as a proposer and a seconder. They have to allow their names to be made public.

Then, 98 other Conservative MPs have to nominate them too but they can choose to remain secret.

Candidates have been collecting the nominations from MPs, either physically or by email, and will submit a form to the 1922 Executive.

I'm told the nominations are checked to make sure they are clearly backing them.

That's quite a lot of admin so candidates will have already booked a slot to go through theirs.

There isn't a lot of time for all this: nominations close at 14:00 BST on Monday; if there's more than one candidate then voting starts at 15:30 BST.

James Heappey is the latest Tory MP to add his endorsement for Rishi Sunak as the next party leader and prime minister

Heappey, a former parliamentary secretary to Boris Johnson, says he has been "agonising all weekend" and Sunak is the right candidate to unite the Conservatives and "restore stability".

As we've been reporting, Rishi Sunak is leading the race to become the next leader of the Conservative Party, and prime minister.

He currently has the public endorsement of 146 Tory MPs. Meanwhile, Penny Mordaunt counts the backing of 24 MPs and Boris Johnson (who has not announced whether he will be running yet) has the public support of 57 MPs.

But who is the bookmakers' favourite?

Image source, .

Up until Liz Truss's government announced the mini-budget on 23 September, the odds for all three candidates by the bookmakers were considerably low - at around 10%.

However they are now saying it is increasingly likely that the former chancellor will be taking the top job at No 10. According to Oddschecker, the likelihood of Sunak becoming PM is 74%.

Paul Bristow, Tory MP for Peterborough has been speaking to the BBC just now. He says he will be supporting Boris Johnson's leadership bid.

Johnson has not declared whether he will stand as a candidate but Bristow says the former PM will be on the ballot tomorrow.

"I'm confident Boris has got the numbers, I'm confident Boris will be in this contest, and in it to win it," he says.

Tory MPs have until 14:00 BST tomorrow to gather the support of 100 MPs if they wish to have a slot in the ballot.

Bristow says Johnson has a mandate and "he won convincingly" the 2019 elections.

Asked whether the government's priorities have changed since the 2019 elections, Bristow says there is more to the Conservative manifesto beyond Brexit, and "so much more to do".

He acknowledged the current economic turmoil, but says it was caused by the Covid-19 pandemic and the war in Ukraine.

As we move into the evening before deadline day for candidates in the Tory leadership race to gain support of 100 MPs let's have a look at what's happened today:

• The big news of the day has been Rishi Sunak's official declaration that he is running to be the next prime minister, saying he wants to "fix our economy, unite our Party and deliver for our country"
• Commons leader Penny Mordaunt had already announced herself as an official candidate and earlier denied that she offered Boris Johnson's team her support in exchange for a prominent post
• Despite Johnson not yet formally declaring, loyalist Jacob Rees-Mogg told the BBC "clearly" Johnson will stand and said he has been told the former leader has the 100 backers needed
• According to our own tally, 227 out of 357 Tory MPs have gone public with their support. We've been able to verify these:
• Rishi Sunak - 146 MPs
• Boris Johnson - 57 MPs
• Penny Mordaunt - 24 MPs
• Labour leader Sir Keir Starmer called for a general election and described the Conservative party as a "chaotic circus"
• The former governor of the Bank of England, Lord Mervyn King, warned that government has to "front up" that the UK faces huge economic challenges on the horizon.

Laura Kuenssberg
Presenter, Sunday with Laura Kuenssberg

Has there ever been a week in politics like this?

A week ago, the new Chancellor, Jeremy Hunt, joined me on my Sunday programme after the sacking of Kwasi Kwarteng.

On Monday – he ripped up the mini-budget.

By Wednesday – the Home Secretary, Suella Braverman had stepped down.

Less than 24 hours later – Liz Truss was gone. She has become the shortest serving prime minister in British history – having been in post for just 45 days.

On my Sunday programme on BBC One and iPlayer - I have been talking to some key players - including, at the time of recording, the only declared candidate, the Commons leader, Penny Mordaunt.

You can listen to 5 Minutes On.. .another Tory leadership contest - a critical 24 hours here.

The number of Cabinet ministers to go public with their support for a particular candidate is growing.

This afternoon, Foreign Secretary, James Cleverly announced his support for Boris Johnson.

Some other key Cabinet ministers backing the former prime minister include:

• Levelling Up Secretary Simon Clarke
• Business Secretary Jacob Rees-Mogg
• Northern Ireland Secretary Chris Heaton-Harris
• Alok Sharma, COP26 President
• Chancellor of the Duchy of Lancaster Nadhim Zahawi
• Transport Secretary Anne-Marie Trevelyan

Also this afternoon Culture Secretary Michelle Donelan said she was backing Rishi Sunak.

Here are the cabinet backers in Sunak's camp:

• Home Secretary Grant Shapps
• International Trade Secretary Kemi Badenoch
• Work and Pensions Secretary Chloe Smith

Image source, Reuters

Rishi Sunak has been spotted stepping out of his central London campaign headquarters and into the back seat of a waiting chauffeured car.

He emerged just after 16:00 BST, and did not speak to the waiting press, the Press Association reports.

Keeping tight-lipped, he ignored questions about the leadership race and whether he will become the next prime minister.

The Culture Secretary Michelle Donelan has confirmed that she is backing Rishi Sunak to be the next prime minister.

In a tweet, she said that "now is the time for unity, stability, delivery and relentless focus".

She joins other cabinet ministers who have put their support behind the former chancellor, including:

• Home Secretary Grant Shapps
• International Trade Secretary Kemi Badenoch
• Work and Pensions Secretary Chloe Smith

Another former minister has given their backing to Rishi Sunak.

Former transport minister Nus Ghani says the next Tory party leader need to "unite and focus on delivery with integrity, professionalism and accountability".

In a Twitter post,, external she adds "I'm backing Rishi - leave party division behind and focus on the country".

It means Sunak has now secured 146 nominations.

There are now under 24 hours to go until the nominations close in the contest.

Johnson-backing MP for Buckingham Greg Smith has told the BBC's Politics South programme he has had two calls with the former PM and has been assured he will run a very different Downing Street administration.

"I think all of us lost our patience over the Partygate issue. But I think he has genuinely learned from those mistakes. He is pledging a very different, tighter Downing Street if he’s prime minister again," Smith says.

The MP says Johnson "understands the frustration that people had. He’s been through the humiliation of having to leave Downing Street a couple of years after winning an 80-seat majority in the House of Commons and he’s absolutely determined that the new Johnson premiership will fix those problems".

"It is time to front up" with the public about the economic challenges ahead including the possibility the UK could face an era that is even "more difficult" than austerity under former Chancellor George Osbourne, former governor of the Bank of England Lord Mervyn King has warned.

Speaking on Sunday with Laura Kuenssberg he painted a bleak picture saying the average person could face "significantly higher taxes" to fund public spending.

He added that you cannot have US-style taxes with European style public spending.

Lord King stressed that government cannot run on a policy of just taxing the rich more because "there isn't enough money there among the rich to get it back".

He added that this does not paint "a very happy picture" for the years to come.

Current Chancellor Jeremy Hunt is due to set out his economic plans on 31 October. So far, none of the Tory candidates for Tory leader have outlined the specific policies they would implement to tackle the economic challenges the country has faced since the market turmoil after Liz Truss's mini budget.

You can read more about Lord King's comments here.

The big unknowns of the Tory leadership racepublished at 14:29 British Summer Time 23 October 2022

14:29 BST 23 October 2022

Jonathan Blake
BBC political correspondent

In a contest that is as unpredictable as it is extraordinary, there are a few things we can say for sure.

The momentum is with ex-Chancellor Rishi Sunak. He has by far the most support among MPs, well past the 100 threshold he needs to formally enter.

There are questions about the true level of support for former PM Boris Johnson. His backers say he has plenty but the number declared publicly is conspicuously low.

Commons leader Penny Mordaunt does not yet have anything like enough support to ensure a place in the contest.

A new prime minister could be installed as soon as tomorrow afternoon and yet we know very little detail about the policies of any contender.

But some big unknowns remain.

Will Boris Johnson stand after all? If not, will he endorse Rishi Sunak whose resignation triggered his downfall? Who will Penny Mordaunt and her supporters swing behind?

A lot is likely to unfold in the hours before the 2pm deadline for candidates to put forward their nominations on Monday.

Image source, EPA

More now from former Home Secretary Suella Braverman - who has endorsed Rishi Sunak to be the next Tory leader.

Braverman, whose resignation came just a day before Liz Truss stood down as prime minister, says Boris Johnson's time in office saw some "remarkable achievements" that "will mark him out as one of our most significant prime ministers in history".

But writing in the Daily Telegraph, she says the UK is currently gripped by "crisis. People are worried about their livelihoods, how they will afford their bills and mortgages".

Braverman says: "Trust in politics is at a low. Our Conservative Party is divided and heading towards a wipeout.

"I want a leader of our party and our country to inspire hope for a better future and raise our spirits. And I need a leader who will put our house in order and apply a steady, careful hand on the tiller. That person, for me, is Rishi Sunak."