The BBC's team of political correspondents bring you news updates, as they happen, on the vote of confidence against the Conservative Party leader Iain Duncan Smith.
Westminster:: Andrew Marr :: 2200GMT
Iain Duncan Smith was not in any sense a stupid man or a bad leader, he was just somebody who in this modern media age didn't quite cut through.
I think a plot to get Michael Howard elected is realistic. Going back to 1990 and the deposing of Margaret Thatcher, the Tories have not been able to stop feuding. That's 13 years of blood letting.
If Michael Howard is the first Conservative leader since then able to call on a broad coalition and inclusive shadow cabinet, then he has a kind of chance William Hague didn't have and Iain Duncan Smith certainly didn't have.
Conservative Central Office:: Mark Mardell :: 2200GMT
It looks increasingly like a coronation. What the MPs want to avoid is a long messy election.
They want to feel they are in charge not the party in the country.
Westminster :: Andrew Marr :: 1945GMT
David Davis's supporters say he hasn't come to any deal. David Davis and Michael Howard are both on the right of the party.
They both share similar groups on Europe.
It would have been an entirely personal ego-driven fight.
Conservative Central Office :: Guto Harri :: 1939GMT
The mood is anxious and a bit despondent.
I can now tell you David Davis is definitely not going to stand for the leadership. He has not done a deal.
I have been told in the last few seconds that Michael Ancram is also reconsidering his position.
We might already be moving towards one person - the shadow chancellor, the former home secretary Michael Howard.
Westminster :: Andrew Marr :: 1918GMT
There is a rumour that David Davis will not stand and will back Michael Howard but there is no confirmation.
Westminster :: Andrew Marr :: 1910GMT
He was not humiliated. He is clearly out. [He was backed by 75 MPs but opposed by 90 MPs]
This is starting to look like a habit inside the Conservative Party.
This result will deeply anger and depress a lot of Tories in the country who voted for Iain Duncan Smith.
He did his level best but as far as Conservative MPs were concerned it wasn't enough.
A lot of Tory MPs are praying they won't have to go through a leadership contest.
Westminster :: Andrew Marr :: 1848GMT
The general feeling is that Iain Duncan Smith has not made it. That is all rumour. It has been for him an emotionally extraordinary experience.
It is an old cliché but for Iain Duncan Smith it really has been the longest day.
Conservative Central Office :: Guto Harri :: 1825GMT
There is a great sense of anticipation here. There are all kinds of cameras, loads of people, including members of the public stopping by to see what all the excitement is about.
When the result comes through just before seven o'clock, then Iain Duncan Smith will come out here and tell us how he sees the situation.
Everybody is anticipating, I think, even those close to him, that the result will be 'Adios, good night Vienna' to Iain Duncan Smith and all he will be doing here will be to leave the stage with a little bit of dignity and credibility intact.
Houses of Parliament :: Andrew Marr :: 1805GMT
The latest word is that it is pretty close. I've just been up to the room where the votes are being taken and only twelve MPs are left to vote.
Iain Duncan Smith's people say it is extremely close. Now of course they would say that, but they are respectable, well-dressed characters, and I've no reason to disbelieve them.
There is an alternative rumour going around on the other side that he has come way, way short of where he needed to be, but I think there is nothing more we can say at this stage, but enough of the rumour, let's wait for the facts.
Houses of Parliament :: Mark Mardell :: 1745GMT
It's been very quick voting, a third of the party had voted in the first half an hour. The atmosphere has been jovial, not heavy.
One supporter of Iain Duncan Smith reckoned he's amassed 60 votes, while a critic said he'd reached 67. Neither of which is good. But that could all be wrong.
And leadership campaigns are quietly getting under way. Michael Howard hasn't been seen to do anything, but there are supporters out there who want him to be leader and there'll still be a lot of talk about whether he may do a deal with David Davis.
Westminster :: Guto Harri :: 1741GMT
I have talked to some MPs today who have grown to think Iain Duncan Smith is alright and were dreading any kind of leadership election.
They've gone off and told me they thought they might just vote for him. At the end of the day, they're not sure what follows is better.
But then there are those who started this for a reason and aren't going to pull out now. Can you imagine waking up tomorrow morning, turning on the radio and Iain Duncan Smith is still leader of the party.
He would not have had a decisive vote in his favour and Tony Blair would be laughing all the way to the next general election.
Westminster :: Guto Harri :: 1723GMT
In the last few hours a number of people who really wanted to see the back of him have been saying that Iain Duncan Smith has been quite impressive over the last few days.
He has worked on the policies and will feel deeply frustrated at 7pm tonight if he was to hand over all that policy work to somebody else who will, in his view, get the credit for it.
I wish I could count the number of Conservative MPs who have told me themselves that they are the most treacherous electorate around. If everyone who's told me, not to mention those telling the whips and the leader, that they're voting for him tonight, he will sail through, with a massive new mandate.
But it's not going to be like that. He might scrape through. I'd be surprised if he does. It's smoke and mirrors all the way.
Houses of Parliament :: Carolyn Quinn :: 1711GMT
Already the air is thick here with talk of deals and leadership ambitions. The supporters of Michael Howard and David Davis have been working overtime. And although nobody would dare to declare themselves until 7pm when the vote comes out, that's when Iain Duncan Smith's political fate will be sealed one way or the other.
People are waiting until 7pm to be able to declare truly what they themselves would like in terms of a political future.
Houses of Parliament :: Carolyn Quinn :: 1602GMT
One MP said that as he was signing his ballot paper, he looked left and right, and he saw two people who he thought were anti-IDS, and he was sure they were ticking the "yes" box to say they did have confidence in IDS.
I think it might be quite difficult to say that all the members of the Shadow cabinet will line up to vote for him. I predict it won't be a 100% turnout from the front bench.
Houses of Parliament :: Mark Mardell :: 1537GMT
Voting has begun in the Conservative party leadership vote of confidence. Ann Winterton was the first to cast a vote.
Among those who have also already voted are former Chancellor Ken Clarke and former cabinet minister John Gummer.
Houses of Parliament :: Carolyn Quinn :: 1516GMT
Iain Duncan Smith has delivered his speech which I understand was very powerful. One MP said to me 'if only he could have delivered these speeches before we might not be in this trouble'.
He talked about the huge learning curve that any leader has to go through, he said 'don't throw it all away now, I understand I've got a lot to learn'. Whoever takes over, if he loses, will also have a lot to learn.
He was very honest, very direct, very self-deprecating. It was apparently quite emotional. I'm told that some MPs in the room were tearful.
It does seem as if people have made up their minds already. The vote is going to be very close. The ballot is secret, so all these MPs saying to me 'I'm going to be loyal to IDS'-well I don't know if I can trust them because when it comes to the secret ballot they'll do what they want.
I know that a large number of MPs have been told by their constituencies not to vote against IDS, and they jolly well are going to do just that, but their constituencies will hopefully never find out.
Houses of Parliament :: Jo Coburn :: 1451GMT
It is extremely dramatic here in Westminster. Iain Duncan Smith's address to the parliamentary party is continuing on the floor above me. There is a huge sense of excitement.
Sir Michael Spicer, chairman of the 1922 Committee, said the precise figures of the vote would be released later on today. So we will have an idea of how IDS does.
Iain Duncan Smith is going to appeal to the parliamentary party saying there's a chance to put forward policies against Labour. But if they have a leadership battle, it will damage the party.
He will also remind them he was elected by a majority of the membership at large and the constituencies will feel that there is a level of betrayal. He will be making a final plea in the hope that he will swing enough votes behind him before the vote starts.
Westminster :: Carolyn Quinn :: 1443GMT
There was a lot of talk and chatter from the mingling journalists and MPs outside committee room 14. Then this hush descended on the corridor when Iain Duncan Smith walked along the corridor and then into the room.
People said it was like seeing a condemned man walking to his hanging. The door slammed behind him and then we heard inside MPs applauding and banging their desks in the traditional way.
Westminster :: Andrew Marr :: 1332GMT
I don't think Iain Duncan Smith is going to be "humiliated", in the word of choice that so many people were using yesterday.
But the lobbies and the corridors are crammed with people who assume already that he is gone and are running and organising campaigns for future conservative leaders - Michael Howard's people are very active and so are those for David Davis.
Houses of Parliament :: Mark Mardell :: 1328GMT
I've just been told that Iain Duncan Smith's speech will be blazingly honest, extremely direct, self-deprecating, but also asking questions about how the Conservative Party got into this state.
So it sounds to me as though he's going to admit to his own faults but also have a go at the party and ask why they have behaved like this. I think people will listen seriously to him and it could change the minds of one or two MPs.
And because there's such a small electorate, and we don't know how many people are going to abstain, one or two votes could be enough.
Houses of Parliament :: Mark Mardell :: 1314GMT
There seems to be something of a late surge for Iain Duncan Smith, whether for loyalty or just sympathy. His people are going around saying they have far more votes than anybody thought - 60, 70 or even 80. Well, that's fine and dandy but if all MPs vote, they need 83.
It only really starts to matter if some MPs think the decision is too difficult to make and abstain. Then it might bring him within the possibility of winning.
It's not impossible that he will survive but I have to say that most people here think that he probably won't get through.
Chingford, Essex :: Vicki Young :: 1309GMT
There is an awful lot of support and good feeling towards IDS here in his own backyard. And amongst Tory party members there's a certain amount of frustration and anger at what has been going on in Westminster.
But there are many here who still feel at this stage that their man can win the day. Talking to people here, many think IDS may have gotten off to a slow start as party leader, but in the last few weeks he's really proven himself.
He's come out and shown himself to be strong, just what a good leader should be. The irony is that it may have all come just a little too late.
Ryedale, north Yorkshire :: Kevin Bocquet :: 1307GMT
The Tory MP for Ryedale was one of the first to demand a vote of confidence in IDS's leadership. Now in a lot of Conservative constituencies that would have been seen as an act of treachery.
But Tories we've spoken to here say they're fully behind their MP and he did the right thing. Support seems to be a good deal less than solid.
College Green, Westminster :: Guto Harri :: 1223GMT
There was a big cheer for IDS when he walked into the chamber of the House of Commons. Yet his own party is likely this afternoon to vote him down as leader. So this was quite weird.
I think even those who don't particularly like him have admired the way he has handled himself over the last few weeks and days.
He then pressed ahead and attacked Tony Blair. It was a pretty good attack and made the prime minister look a bit shifty and a bit uncomfortable.
But of course at the end of it, will it change anything? No. It will just be a memorable swansong, unless we've all got it wrong at this point.
Millbank, Westminster :: Carolyn Quinn :: 1157GMT
When we have the result this afternoon I think very shortly after that, if IDS has lost, you will quickly see other candidates coming forward.
They want to make sure they get one candidate to put forward. Deals are already being done, I hear, deals to put one option to the party in the country.
College Green, Westminster :: Guto Harri :: 1101GMT
It's not possible to predict the outcome for this afternoon. Traditionally the Conservative Party in the House of Commons is known as the most treacherous electorate. People tell one camp they are going to vote for them and then go off and do the exact opposite.
On this occasion that could work to IDS's favour. those around him have been tallying up the votes. He could actually pull it off. But very few people deep down think tonight that he is going to do doing anything other than step onto the backbenches.