The Tories' tipping point?

By Nick Assinder BBC News Online political correspondent

Well, he is still there, fists up, head down, jaw clenched.

Mr Duncan Smith remains defiant

Indeed, the worse it gets for Iain Duncan Smith, the more determined he appears to be to hang on in.

He has told his shadow cabinet that he is going to lead the Tories into the next general election.

And, as he showed on BBC's Breakfast with Frost programme on Sunday, he is prepared to force a leadership election if necessary, no matter how bloody and divisive that may be.

Even so, he seems determined not to follow the one piece of allegedly helpful advice that he should "do a Major" and instigate that vote of confidence himself.

Head on

His continuing fury at the whispering and plotting is certainly understandable.

It is now weeks since it all kicked off, and his detractors still have not summoned up the bottle to come out from the shadows and confront him head on.

That may be leading him to believe they have not got the courage to follow through their plotting to the bloody end.

Whatever the merits and however significant the challenge really is, this leadership crisis has now grown a life of its own.

Each day's media reports of plotting, as a raft of shadow ministers have admitted, causes significant harm to the Tory party's public image.

The question is whether it has reached a stage where the all-important grassroots party, along with some big donors, have decided it is simply no longer worth trying to keep Mr Duncan Smith.

Tipping point

It seems highly likely his chief whip, David Maclean, has given him a realistic assessment of his current position.

"Betsygate" inquiry has dogged IDS

He has denied saying Mr Duncan Smith had lost his party, and is more likely to have said he was in danger of losing his party as the uncertainty continues.

What all sides are watching is whether the tipping point has been reached.

Along Westminster's corridors it is certainly difficult to find anyone privately ready to bet on Mr Duncan Smith surviving until Christmas.

Even those who have until now believed the plotters were all talk and no action are beginning to change their minds.

And, while the plotters have so far failed to get the 25 names needed to spark a leadership election, their task may well be getting easier given that the vast majority of Tories simply want this nightmare to end, one way or another.

One explanation given for the recent surge in speculation is that some of the plotters have realised the inquiry into the way Mr Duncan Smith employed his wife may actually work in his favour.

Unite the party

If he is cleared, he will be able to portray the affair as a disreputable attempt to destabilise him, and the troops may then rally around.

So there is a feeling that the dissenters need to move before the inquiry concludes.

There are also rumours, which started towards the end of the party conference two weeks ago, that they have finally decided on a leadership contender or contenders.

The words "Michael Howard plus one" are being bandied about.

The one could be Oliver Letwin, Kenneth Clarke, David Davis or virtually anyone else who takes the fancy.

The aim of the exercise is to find a candidate or team who can unite the party and, as a result, avoid a leadership election that would go to the party membership.

That is still the plotters' greatest dilemma.

Mr Duncan Smith's dilemma is to convince the party it would be no better off without him.