THERE is a regular, plaintiff cry from the “moderate” centre of politics that goes like this: “Can we have the grown-ups back?”

It’s a cri de coeur from those who believe in their hearts that centrist politics comes from sensible, grown-up heads. Their ideas are adult, thought-through, sensible. The left’s ideas are naive, silly, childish and unachievable.

But drawing the left as the Kevin and Perry of politics and the “moderates” as their long-suffering parents is itself based on a deep strain of naivety among the supposedly “sophisticated” technocrats. A naivety that has been on display for decades.

In August Labour’s new MP for North West Durham, Laura Pidcock, said she disagreed firmly with Tory MPs and had “absolutely no intention of being friends with any of them.

“I have friends I choose to spend time with. I go to Parliament to be a mouthpiece for my constituents and class; I’m not interested in chatting on.”

Her comments are much milder than those of Anuerin Bevan, who spoke of a “a deep burning hatred for the Tory Party” because the pain they inflicted on the nation in the 1930s made him feel they were “lower than vermin.”

Pidcock’s views are well within the Labour tradition. But her straightforward answer to a question from the “Skwawkbox” website inspired a wave of criticism from “moderate” Labour and Tory commentators.

Pidcock’s insistence that she goes to Parliament to work for her constituents, not make friends with Tory MPs was called “childish” and the politics of the “student union” by Conservative and “moderate” Labour commentators.

They think being angry at Tories isn’t “grown up” and that it won’t “get things done” — which is odd, because Pidcock saying she wants to go to work to get change for her constituents, rather than treating the House of Commons as a social event, sounds pretty businesslike.

And the much angrier Anuerin Bevan was able to “get things done” — chiefly founding the NHS — precisely because he was driven by strong feelings.

The Pidcock-patronisers are part of a broad trend. One that says any attempt to change things on the scale of Jeremy Corbyn’s Labour manifesto is naive, that his wing of Labour is made up of childish, unrealistic dreamers, and that they are not “professional” politicians.

In February the Guardian spurted out this nostalgia for their “moderate” daddy in an editorial on Tony Blair’s latest pronouncement: “Mr Blair reminds us what it was like to have grown-ups in charge.”

This “let’s have the grown-ups back” call is repeated by a lot of sad moderate dads. It makes me wonder where they have been for the past 17 years. Because the “centre” has been anything but mature. Instead, it has been the place of the most naive and embarrassing wishful thinking .

We saw a very embarrassing recent demonstration of this naivety when James Chapman, an ex-Daily Mail political editor, former adviser to George Osborne, and current adviser to lobbyists Bell Pottinger, declared he was setting up a new “centrist” party called the “Democrats” to “stop Brexit.”

Many “sensible,” “moderate” Labour commentators enthusiastically took Chapman’s amateurish plan seriously.

Everybody one-click further to the left could see some Tory lobbyist was not the answer to anything, that this would not work as a grassroots project and that it was just wistful dreaming.

So it proved. The credulity of the New Labour and David Cameron Tory supporters of this half-baked scheme was embarrassing. But in truth it was not new.

Being credulous and not understanding the “real world” are the hallmarks of many claiming to be “realists.” Like the naivety of Brown and Blair in backing the Private Finance Initiative.

Only the truly innocent would believe handing control of school, hospital and other public buildings to bankers and contractors would be “efficient.” The left warned it would be a rip-off. And it was.

Or the foolish belief that handing sensitive public service contracts to a mix of caterers, security firms, and totally dubious outfits like Sodexol, Serco, G4S or A4e would bring new, exciting methods to the welfare state — rather than the old fashioned scams and rip-offs that the left warned about.

Or the pre-crash naivety of believing unregulated banks would deliver prosperity for all, for ever.

This wide-eyed view of corporations was ingrained into New Labour at the start and happily picked up by the Cameron crew.

From the very beginning New Labour people fell in love with all corporations, including the obviously crooked. Peter Mandelson spent much effort trying to get Labour to love the US energy firm Enron.

People on the left looked closely at Enron’s record of safety breaches, economic and environmental crime, and warned they were bad news.

But New Labour’s leaders insisted on taking cash from Enron (as did the “sensible” Fabians) before the firm collapsed under the weight of its own criminal behaviour.

New Labour’s leaders also decided the best way to celebrate the Millennium was not to — say — build new hospitals. Instead they thought a corporate sponsored entertainment palace celebrating all that big business could offer was a wise plan. Only a true sucker could buy the Dome, but that’s what they did.

With criminal credulousness the same “moderates” believed a US Republican government stuffed with oil men would lead a “liberation” of Iraq, rather than the badly run corporate-led occupation that we got.

With the eternal sunshine of the centrist mind, many saw the Iraq project go bad, but then expected the re-run in Libya in 2011 to be ok. Cameron and “New Labour” types queued up, wide eyed, to walk into that trap.

In truth, it is really naive to believe there is a technocratic policy in the “centre” that can solve big problems. It is childish to believe that big corporations don’t try and break rules to squeeze out profits, that rich people don’t avoid tax, that US governments want to go to war to “liberate” anyone.

The past 200 years have shown us that “grown-ups” can change society by using popular pressure to redistribute money, to regulate big business and to reform the state in favour of the majority.

Socialists pushed for big reforms that began as ideals, but became practical realities, where centrists averted their eyes from the failures in the existing system.