On its final day, the Conservative conference has resembled a convict on death row immediately after a stay of execution. The prisoner may have longed for a full pardon but will have to make do with a temporary reprieve.

So dire is Theresa May’s predicament — a daily battle for political survival — that leaving Manchester as she does, battered but not yet supplanted, must feel like an achievement of sorts. But there has been no reversal of fortune in the past four days, no spectacular plot twist. This is respite, not rescue.

It was perhaps inevitable that the Prime Minister should close the conference with a unity plea, reminding her senior colleagues that their sole concern should be the wellbeing of the British people: “Not worrying about our job security but theirs. Not addressing our concerns but the issues, the problems, the challenges, that concern them. Not focusing on our future but on the future of their children and their grandchildren.”

That is unarguably so. But it is a measure of the party’s mood of torpid mutiny and sullen dissatisfaction that May had to spell this out at all. In government for more than seven years, the Tories should not need to be reminded of this most basic political truth.

What was meant to be a gathering of tribal restoration — a morale-boosting rally after the fiasco of the general election — became, not for the first time, The Boris Johnson Show. Though his speech yesterday was freighted with declarations of loyalty, it represented no more than a truce between the PM and her Foreign Secretary. His antics have dominated this conference, ensuring that his name is on everybody’s lips and that the collective purpose of the gathering has been almost completely eclipsed by one man’s ambition.

For that, many of his most senior colleagues will never forgive him. Though he retains the affection of many Tory activists, the parliamentary party is increasingly uncertain of his fitness for the highest office. As one normally amiable Cabinet minister put it to me: “Boris has behaved like a f***ing c***.”

That said, May must share the blame for this political farce. The post of Foreign Secretary is one of the great offices of state, one of huge responsibility and significance. Whoever holds the office is not only the nation’s most senior diplomat but a primary member of the Cabinet. The incumbent cannot be allowed to behave like a freewheeling backbencher — in this case, the self-appointed tribune of Brexit Britain.

Yet that is precisely what Johnson has been permitted to do. Yesterday, May took refuge in the feeble claim that a strong leader does not surround herself with “yes men”. That may be so. But a strong leader does not license even her most colourful colleague to flout collective responsibility when it suits him. Those angry with the Foreign Secretary are no less dismayed that the PM chose, ultimately, to appease him. Though he stepped back from the brink of overt rebellion, Johnson leaves this conference exactly as he hoped to: with his name in lights.

Worse, this battle of personalities has distracted the party from the real task it faces. To be fair, the PM has some inkling of what needs to be done. She understands that the old economic consensus has been challenged with surprising success by Jeremy Corbyn. She has not lost sight of the need to appeal to those who still distrust the Conservative Party, particularly ethnic minority voters. There are still flashes of the passion she displayed outside No 10 in July last year as she pledged to tackle “burning injustice”.

By no stretch of the imagination, however, has this intuition translated into a sense of collective mission and dynamic resolve. Precisely when the party most needed to raise its horizons and offer a revitalised Conservatism fit for the future, it has presented the voters with little more than an inventory of modest proposals and minor reforms. This was a moment for the grand Imax screen, not political pixellation.

One of the reasons the Tories performed so disappointingly in June is that they failed to defend their record since 2010. In Manchester, however, they made the opposite error, which was to rely too heavily upon past glories and the ideological hegemony of Conservatism since the Eighties.

If the party is serious about winning over younger voters it must ditch this habit as a matter of urgency. Today’s 40-year-old was 12 when the Cold War ended: it is absurd to expect his or her support on the basis of a global struggle that ended in 1989. The “Winter of Discontent” is as historically remote today as the struggles of 1940-41 were when Margaret Thatcher came to power.

The way to beat Corbyn is not to relitigate the past, or to refer scornfully to his love of socialism in Venezuela and Cuba, as though such allusions will strike a chord with the electorate. Jokes about the Labour leader being “Caracas” have the self-satisfied whiff of Tory clubland about them. They mean nothing to voters who, quite rightly, want to hear less sneering and more about what Conservatism could possibly have to offer them in an age of anxiety, insecurity and volatility.

The Prime Minister lives to fight another day — just. But she and her party have achieved nothing of substance in a conference that should have been the scene of unflinching honesty, intellectual daring and shared renewal.

This week, the Conservatives have oscillated between babble and aphasia. They have conspicuously failed to explain why the voters should care what they say. They have blown yet another chance. How many more can they expect?

