Iain Duncan Smith will never become Prime Minister. And the Tories know it

The Conservative Party, the most formidable fighting machine in political history, has become despondent and spineless

The Tory opposition is in breach of the Trade Descriptions Act, and doubly so. It is neither functioning as an effective opposition nor as an effective Tory party. Throughout its modern history, the party has regarded itself both as the national party and as the natural party of government. Believing that it ought to be almost constantly in power, it always found opposition an unnatural and frustrating state of affairs, which could only be endured by harrying the government towards its quietus.

That has ceased to be true. The Blair government is in trouble on all fronts. It has lost its intellectual momentum while the PM has forfeited his moral credibility. Any competent opposition ought to be revelling in its opportunities. This one slips to third place in a by-election.

Equally, any serious Tory, appalled at the thought that such a worthless government could be re-elected, ought to be straining every sinew to prevent such a wretched outcome. Instead, there is widespread resignation at the prospect of another inevitable defeat.

Though there are plenty of able Tories in Parliament, but their collective behaviour is that of power-shy pygmies. The Tory party, that mighty instrument, the most formidable fighting machine in political history, has become despondent, enervate and spineless.

Yet the problem is easy to identify and not hard to correct. The Tory party is going nowhere because it does not have an effective leader. This is widely acknowledged in serious Tory circles. Iain Duncan Smith has the support of the Dunderhead wing of the Shadow Cabinet: Bernard Jenkin and John Hayes, two of his closest friends, plus Quentin Davis, another close friend and a very clever man, with a catastrophic absence of nous. Oliver Letwin and Michael Howard - no dunderheads they - also defend him staunchly, because they place loyalty above political judgement. Beyond that, almost every Tory frontbencher and about 90 per cent of the backbenches make no attempt to conceal their awareness of his deficiencies. They know that he neither will be Prime Minister nor should be, because he is not up to it. Yet nothing is done.

If IDS had been a chief executive or the manager of a sports team, he would have been sacked by now. Only in the Tory party can he survive. A party which used to be so demanding of its own leaders in order to be so ruthless towards its opponents has learnt how to acquiesce in mediocrity.

When pressed as to why they refuse to act, Tory MPs give two reasons: the absence of an obvious alternative and the damage that would be inflicted by a three-month leadership campaign. Neither is valid.

Almost all Tories wish that transplant surgery were more advanced, because they know whom they would like as leader: Ken Clarke, with Michael Howard's views. But even in the absence of such an ideal candidate, there are plausible alternatives, especially as there is no longer any risk that an unreconstructed Ken Clarke could win, and split the party.

Given that William Hague could not be persuaded to run and that Michael Howard is, alas, unelectable, a leadership contest would probably come down to David Davis versus Oliver Letwin. Mr Davis would do a much better job than IDS. Mr Letwin, long this column's favourite, is one of the classiest acts in British politics. I find that he has overwhelming support among thoughtful people who are not intensely political but who have a strong sense that as the Tory party lost its way about a decade ago, there was no point in voting for it. Mr Letwin would win them back, instantly.

He would also win over millions of voters who are now reluctant to go to the polls. Though they may seem to approach politics from behind a carapace of cynicism, many of them would be in the market for decency and honest leadership. If anything, Mr Letwin has a dangerous excess of decency and honesty, but after Tony Blair, that is a fault on the right side.

Nor need the party necessarily fear the consequences of a long leadership campaign. Some Tory constituents would certainly be unhappy. But very many more would be delighted to see the back of a failing leader, and why should it be assumed that the wider public would blame the Tories, when they are so unwilling to be impressed by IDS?

Even the length of the campaign need not work against the party, as long as it took the form of a sustained debate. There would be an obvious contrast between the Tories, willing to discuss big issues in a serious manner, and Mr Blair, spin-corrupted to his soul.

At the moment, only a small minority of the electorate knows what the Tories stand for, and how could IDS ever put that right? But three months' publicity for the clear and forceful expression of fresh Tory thinking could create the beginnings of an electoral momentum, which a new leader would enhance.

Apropos of electoral momentum, Downing Street is already planning its next campaign, and IDS is crucial to its calculations. Labour intends to do everything possible to heighten the presidential nature of the contest, in the belief that even voters who are disillusioned with Tony Blair could be frightened back to New Labour by the thought of IDS in Number 10. Labour's strategists would be mightily dismayed if the Tory party did decide to dispense with IDS's services. So why do Tory MPs choose to play the role which Labour's scriptwriters have prepared for it?

The Liberals are also hoping that IDS stays in place. In one respect, that is monstrously unfair to the Tory leader. However bad he is, he is many times better than Charles Kennedy. I doubt whether Mr Kennedy could claim the respect of a single MP outside his own party, and there is plenty of grumbling within it. But this would not necessarily prevent him from capitalising on IDS's inadequacies.

During the election, the Liberals will assure voters, as they always do, that they are nice, good, honest people, unlike the rest of those politicians who are so rightly despised. If IDS is making no impact, except negatively, the Liberal tactic will prosper and they will move into the vacuum. By 2005, the politicians may well be facing the most disillusioned electorate in British history. Those are circumstances perfectly designed for further Liberal gains, mostly at the Tories' expense. Many Tory MPs recognise the danger, so why are there not 25 of them prepared to initiate a leadership campaign to avert it?

Tory conferences always end with "Land of Hope and Glory". This year, it ought to be Tennyson's "Lotos-Eaters":

"Surely, surely slumber is more sweet than toil, the shore

Than labour in the deep mid-ocean, wind and wave and oar.''

"Why should life all labour be?'' Odysseus's men complained.

If the Tory party continues in its Lotos-slumber, that is precisely what it will be - and Liberal too.