It has become commonplace to remark that there exists in Britain a mainstream political grouping that seems to be dwelling on another planet. Lost in fantasy, harking back to days long-gone, it lives on illusion. Time and the modern world have passed it by. Fleet Street and fashionable opinion rage against these mulish daydreamers for turning their backs on the voters and depriving Britain of an effective opposition.

And all this is true. In only one detail are Fleet Street and fashionable opinion mistaken. They’ve got the wrong grouping in their sights. It is not Jeremy Corbyn, John McDonnell and their crew who fit this picture: it is the Labour moderates.

Neo-Blairites and neo-Brownites are in cloud cuckoo land — and in control of the parliamentary Labour party. In vain do they beat their fists against the new ascendency in their party. In vain do they prove, by opinion poll after opinion poll, that old-fashioned socialism will never win the next general election. They’re missing the point.

So are their friends in the newspapers. Media fury tends not unnaturally to be led by wonderfully eloquent writers — such as Dan Hodges, or my own newspaper’s David Aaron-ovitch and Philip Collins — who are well-grounded in Labour’s politics and have at least one foot in the party’s recent past. Too angry with their new enemies to take a cooler look at their old friends, they seem to miss what drives the left and its appeal.

Perhaps a convinced and rooted Conservative like me can understand better why an ideology — a clear, strong theory about what drives human history — is proof against the wisdoms of marketing and the headlines about opinion polls. You see, we Tories have such an ideology.

Suppose, reader, that you were a rank Conservative and a convinced believer in free-market economics. And suppose that Keith Joseph and Margaret Thatcher had never lived and that after the 1970s Britain had continued its slow slide towards a command economy; and that lunacies like Shirley Williams’s scheme for controlling prices in shops had bedded in, and wages and incomes too had come under central control. It’s imaginable, isn’t it?

And suppose we Conservatives all feared, as we did fear, that a supine British electorate was growing passive and acquiescent in the swaddling clothes of the cradle-to-grave nanny state. Suppose you feared, as we did fear, that our own Conservative party, judging further resistance futile, was becoming dangerously compromised in its embrace of the ‘mixed economy’.

Suppose, finally, that despite these lean years for our own political faith, you and I refused to give up the fight. Though sneered at as renegades unwilling to accept that times had changed, suppose we bid to change our party’s direction. Mainstream opinion, and swaths of Labour and Tory MPs would have laughed at us. ‘Look at the opinion polls,’ they might jeer, ‘can’t you see that the voters out there have grown reliant on the comfort-blanket of the welfare state? All the evidence is that the British don’t like isms and distrust your free-market dogma. Sure, you poll a steady 15–20 per cent, but how are you going to break out of that core vote and win over the floating voters unless you “triangulate” and strike a middle position between the right and reality?’

‘Ideologues! You wait for the next local/mayoral/regional elections! The voters will dump on your antique certainties. Move on, dinosaurs, or you’ll drag your party down.’

Reader, can you see how, to you, this barrage of incredulity misses the point? Unlike your detractors, you have a belief. As well deride market forces as deride gravity: you know that history will prove you right. You understand the mainsprings that drive human behaviour. You understand the clockwork. The theory you hold about what motivates individuals and families, and what drives successful national economies, teaches you that in the end socialism must fail.

But when? Your theory doesn’t tell you, of course. Your mission is to proselytise. The early Christians were hardly an overnight success in Rome. It may be years — it may be a decade — before the nation wakes from welfarist slumber. You’re patient. Secretly you accept that your faction will take a beating in a string of proximate elections, and maybe even the next general election. But Kipling’s Gods of the Copybook Headings will finally visit their revenges on the smug political establishment now dancing before its socialist golden calf.

So you would stick to your guns. Your doctrine gives you an explanation for the world: one that cannot be gainsaid. The product is fundamentally sound, whatever the marketing people may tell you about the most recent customer surveys.

So it is with the Corbynites. I don’t (and nor perhaps do you) believe that their theory of politics and economics is correct; and I doubt Mr Corbyn is the man to take his movement forward for many years longer. He’s an enabler, a prophet in the wilderness. Not for him arrival at the Promised Land. He lacks the political skills that his shadow chancellor, John McDonnell, showed on the Marr programme last week. He’ll probably hand on the torch before the next election.

But don’t imagine the torch will be extinguished, or that (latest madness of the ‘moderates’) the flame can be hidden by stopping anyone who carries it from even standing for the party leadership. The worst thing the parliamentary Labour party could now do would be to try to triangulate between the hard and the soft left. Dan Jarvis and Hilary Benn, defined by what they are not, will never say anything interesting.

And Corbynites are right about this: the Labour moderates are indeed latent Tories. They’ve accepted, as did Tony Blair, the broadly Conservative ruling spirit of the age. Their judgments are safe, but safe to the extent that they are Conservative judgments. They have no religion of their own. Corbyn does. We Tories do. It is Labour’s moderates who are in denial.