Never forget that new Labour was built on a psycho-drama. Peter Mandelson recently described his tormented relationship between Gordon Brown and Tony Blair thus: “I was the third person in the marriage. I was the casualty.” How very Princess Diana.

Asked by The Times why Brown wanted to lay the past to rest, Mandelson laid it on with a trowel: “There is an emotion, a sentiment which you don’t see, a gift for friendship and warmth he doesn’t always bother to put on public view. He is a private man. You know from the way he has been brought up. It is a bit like me in a way. You don’t show emotions in public. I think we may come from similar backgrounds, similar maternal influences.” That must explain why they once behaved like that other famously mother-fixated fellow, Norman Bates from Psycho.

The fires still burn in the longest ménage à trois in political history. Brown and Mandelson are back in harness and the third charmer is never far from their thoughts. First secretary, lord president of the council, deputy prime minister in all but name, Mandelson is clearly relishing his recall to the centre of power. He is the last prop holding up this ramshackle government.

Saving Gordon is proving to be a full-time job: Mandelson can’t be spared to fulfil his ambition to become foreign secretary, just like his grandfather Herbert Morrison. At the time of the disastrous reshuffle it was he who saved the day, remember. A few more ministerial resignations and it would have been curtains. The former Prince of Darkness, now Gordon’s Good Angel, persuaded the last Blairites not to quit. Now he even pops into No 10 and tells the PM to stop e-mailing and go to bed.

His is a rare voice of sanity. Brown, seduced by the notion he could rerun his favourite campaign of “Beware the Tory cuts”, has been stubbornly denying that a reelected Labour government would have to make cuts too. In poll after poll the voters say they don’t believe him. Last Wednesday Mandelson finally called a halt to this nonsense. “There will be spending choices and a growing need for greater efficiency across the board, and less spending in some programmes,” he purred.

The first secretary has a nuanced message: “Trust Labour to make the right cuts; the Tories will do it heartlessly.” That doesn’t mean handing David Cameron a pass on the economy. In another interview, Mandelson peremptorily seized the Treasury rudder, ruling out a comprehensive spending review that could be mined by the Tories. The chancellor, Alistair Darling, may now offer a scaled-down version designed to publi-cise the services Labour will defend from cuts. No wonder friends call Mandelson “the supreme leader”.

There are the outlines of a fightback strategy here, though No 10’s stubbornness has cost the government an entire summer. Our poll today puts Labour 17 points behind the Conservatives. “Peter got what he wanted with the person he never wanted it with,” wryly observes one friend of Tony Blair. TB would have taken his friend’s advice from the start. But what can you do with inferior mate-rials? “If Peter wished to withdraw his support, Gordon would be finished,” adds Tony’s friend, “but I can’t see the headline ‘Mandelson ditches Brown’.”

To throw over Brown in 1994, when Blair clearly was the most electorally appealing Labour leadership candidate, was good judgment. To ditch Brown a second time would be to chisel the word “treacherous” on the tombstone of Mandelson’s own political career. He hasn’t the heart for it. Yet Mandelson’s loyalty to the third man in the marriage is not forgotten. It has even been claimed that on the night of the reshuffle he fought for the Iraq war inquiry to be held in camera to spare Tony’s blushes. Friends of Mandelson deny it absolutely and I for one believe them. He was far too busy that evening hitting the phones.

Blair has even more jobs than Mandelson has titles - Quartet representative to the Middle East, climate change czar and adviser to the world’s religions, to name but a few - but one more challenge still beckons, the presidency of the European Union. The post will be created if the Irish ratify the Lisbon consti-treaty in October. Brussels is giving them a second chance to “get it right”, having “got it wrong” in last year’s referendum. The Poles will then follow suit, though the Czech president, Vaclav Klaus, may put up more of a fight.

Last year, at the meeting of the international great and good in Davos, Mandelson, then still a European commissioner, was already canvassing for Blair to get the No 1 job. TB, in the words of another close friend is “seriously relaxed” about getting the presidency. He will not campaign for the job: as a former prime minister keen on his dignity, he would only accept being drafted. His post-No 10 career is, after all, lucrative and fulfilling. The Middle East’s complex politics are fascinating and, despite their differences, Blair gets on surprisingly well with Binyamin Netanyahu, the hawkish Israeli prime minister. But to end his career as a president, able to talk on level terms with Barack Obama, would be tempting.

Glenys Kinnock last week let slip that Brown has come round to backing a Draft Tony campaign. In the past, having Blair in Brussels would have been his worst nightmare. After all, he fought for 10 years to take his crown. But with his fortunes at a low ebb and with Mandelson in the ascendant, Brown has conceded. Blair made it easy by behaving courteously towards his successor, keeping out of politics.

But even Mandelson’s powers of persuasion can’t fix this one for Tony: he will need the assent of 26 other governments too. It is by no means certain he will get it. Blair is, in the words of Charles Grant, director of the Centre for European Reform, “a political orphan” in Europe. The left think he is too right-wing, pro-American and tainted by the Iraq war. Spain’s ruling Socialist party thinks he should be on trial for war crimes. The centre right do not acknowledge him as one of their own. And yet . . .

Opinion in Europe is divided by the Little Man or Big Man camps. Supporters of a Little Man president would like a bureaucrat in the mould of Luxembourg’s prime minister, Jean-Claude Juncker, a man with an eye for the fine detail of intricate agreements. Many heads of government – and until recently Brown might have been one of them – dislike the idea of being bossed around by an international superstar.

Supporters of a Big Man, however, say that only a real statesman will do for negotiations with great but intractable powers like Russia and China. After the Russian invasion of Georgia and the crisis over Europe’s energy supplies, this view is gaining traction. Russia’s ruler, Vladimir Putin, for instance, would not let a man like Juncker into the room. Blair once confronted Putin to his face and would do it again.

Sarkozy of France and Italy’s Berlusconi would likely support Blair. The eastern Europeans and the Nordics like him too. Merkel of Germany is equivocal but open to persuasion. Federalists, however, are suspicious of a candidate from a country that has held aloof from the euro and the Schengen agreement on immigration-free borders. And they point to a hostile British opposition that looks a good bet for government.

William Hague for the Tories has denounced the proposal. Camp Cam-eron says stories that the Tory leader would secretly support a Blair candidacy are “absolute tosh”. “He has no enthusiasm for a president, he has no enthusiasm for Blair,” says one of his inner circle. Our poll shows British voters agree. But might federalists favour Blair in order to trip up the sceptical Tories?

Perhaps it’s all a pipe dream. But if Tony got to Brussels, favours could be returned. Mandelson would make a fine presidential chef de cabinet. And when Gordon lost the election, his chums could fix up a big international job for him, too. We might be stuck with the three of them for another decade or so. This psycho-drama could run and run.

Times Recommends

• We have kit and leadership. Let’s go
• Behind the scenes at the biggest deal
• Conferences — what a waste of money