The search is on among the party's would-be assassins for one big enough to take courage in both hands and wield the dagger, writes FrankMillar, London Editor.
These Tories, it seems, have murder in mind. True, they would prefer Iain Duncan Smith to retire quietly to his room, whisky in one hand and revolver in the other. But failing an act of supreme sacrifice the search is on among the would-be assassins for one big enough to take courage in both hands and wield the dagger.
Rather like Ulster Unionist leader David Trimble, "IDS" has so far been blessed by the quality of his opposition.
A former party apparatchik has described the present mutinous crew as "the most historically duff generation" of Conservative MPs. And their courage may yet fail them. Instinctively they feel they need to kill-off IDS and ensure a bloodless succession.
Yet they flail around in the Blackpool storms seemingly no closer to agreement on whom to bestow the tarnished Tory crown.
Certainly they face no shortage of pretenders, even if - in the sum of their parts - they hardly amount to an embarrassment of political riches.
David Davis, Kenneth Clarke, Oliver Letwin, Michael Howard, Michael Portillo, even Tim Yeo (Tim Who? you demand) is considered "in the frame".
Indeed some Tory MPs in various states of sobriety hanker for what suddenly seem the not-so-bad-old-days and think maybe they should send out the call for William Hague.
Then there is the problem of the electoral process bequeathed by Mr Hague - designed, as it was, to extend the electorate beyond the parliamentary party to include rank-and-file members and so protect the former leader from precisely the sort of insurrection now threatening his successor.
Ken Clarke articulated what in normal circumstances would pass for conventional wisdom the other day, protesting (if a touch weakly) that the party can't indulge in a leadership crisis every other year. What would the public make of it, fretful MPs ask, if they decided to have another just two years after the party in the country - in defiance of the majority of MPs - elected IDS to succeed Mr Hague? And if all those proclaiming allegiance to Mr Duncan Smith while burnishing their own claim actually entered the ballot, wouldn't the resulting blood-letting over many months simply further undermine the party's claim to be taken seriously as an alternative government-in-waiting?
One hard-nosed Conservative - who originally backed IDS and is now impatient to see the back of him - discounts these reasons for inaction. First, the whole argument for changing leader now is born of recognition that the Labour Party is almost certainly going to win the next election - and that the increasingly urgent Tory task is to stop it winning a fourth. In addition, the source calculates: "The punters aren't listening now, probably won't pay much attention to a leadership campaign, and in six months' time will have largely forgotten that Iain was ever there."
On his election Mr Duncan Smith himself said the voters would probably form a view of his leadership within a period of three or four months.
Two years on the relentless message is that they have, and that his leadership thus far can be deemed a failure. It is not that IDS arouses strong feelings among the public or that many deeply dislike him. They just don't rate him. The anecdotal evidence suggests most people simply do not believe that IDS will ever be prime minister. Some focus groups certainly record a strong and hostile response to some being touted to replace him, like Michael "something of the night about him" Howard.
IDS by contrast seems to struggle to provoke even a neutral response from voters. And the shocking message from this week's pre-conference YouGov poll was that the numbers rating Mr Duncan Smith's leadership as "weak and ineffectual" has actually risen over the past 12 months, with just 3 per cent giving his leadership a positive rating. The irony is that IDS has notched-up some successes.
He has becalmed his party over Europe, encouraging eurosceptics in the belief that Kenneth Clarke can never succeed, thus removing the risk that a europhile leadership would split the party in the country should the Blair government ever get round to holding a referendum on the euro.
Mainstream Tories also appear to have dropped their obsession with sex and "alternative" lifestyles. And in Blackpool this week shadow ministers have unveiled a raft of eye-catching new policies - for eroding the power of government and extending choice in the public services - which could give a radical cutting-edge to the party's opposition to the Blair government.
However, by last night the platform's best endeavours had failed to drown a rising chorus of concern that Mr Duncan Smith is not equipped to sell any policy package and that the punters simply refuse to hear him; that despite the clear collapse of trust in Mr Blair, Labour retains the lead at the height of real mid-term unpopularity; that IDS ranks behind Charles Kennedy in the public's assessment of who would make the best prime minister; and that it is no longer inconceivable that the Liberal Democrats might actually replace the Conservatives as the official opposition at Westminster.
Hence, this morning, in the words of the Daily Telegraph, Mr Duncan Smith must perform some magic.
As one party insider puts it, the "Torygraph's" support for IDS in the leadership election was the equivalent of the Transport and General Worker's Union deploying its block vote at a Labour conference.
It isn't hard to imagine the tremor of fear which must have hit the leader's office, therefore, on Monday morning, as its editorial warned: "If all belief fails, his continuation in the leadership would make no sense."
The signatures of just 25 Tory MPs are needed to force a confidence vote.
Mr Duncan Smith might see the writing on the wall should the paper - having served notice that this is his last chance - join them in concluding that he had blown it.