He hasn't gone away, you know. So watch out, Clare. Mind your back, Jack.
The Home Secretary, Jack Straw, had fair warning. When Peter Mandelson bowed to the verdict of that "kangaroo court" back in January, Mr Straw calmly explained his colleague's second enforced resignation from Tony Blair's cabinet. The then Northern Ireland secretary had had to go, said Mr Straw, because he had told "an untruth".
Once Mr Mandelson had recovered from his moment of madness he confidently predicted that the Hammond inquiry would clear him of lying or wrongdoing in the Hinduja "cash for passports" affair.
And "friends" let it be known that in that event Mr Mandelson would expect an apology from the Home Secretary.
Hammond duly cleared Mr Mandelson, and Mr Straw may now be wishing he had similarly obliged. Likewise the Overseas Development Minister might be ruefully reflecting on her very public glee at Mr Mandelson's fall. As Labour MPs reportedly drank Commons bars dry of champagne, Ms Short exulted: "Peter Mandelson is over."
Well, by all accounts he's back. Incredibly, sensationally, the twiceresigned minister is back by Mr Blair's side - or, at any rate, by the Prime Minister's ear. "Delay to election shows Mandelson still has Blair's ear" ran the headline over an article by Peter Kellner, whose known inside track to the Blair camp suggests this is indeed the state of the world as viewed from inside No 10.
Elsewhere, too, an abundance of clearly-informed articles tell us that it was Mr Mandelson - alongside focus group guru Philip Gould, Lord Falconer and the Blair gate-keeper, Anji Hunter - who prevailed against the majority view within the cabinet, and the overwhelming instinct of Labour MPs, that the general election should have gone ahead as planned on May 3rd.
Meanwhile Andrew Rawnsley, whose brilliant book Servants of the People laid bare the personality fault lines at the heart of the New Labour project, explains why there is suddenly "a cold shudder around the cabinet table".
According to his account, Mr Mandelson's judgment about himself may be terribly unreliable, "but Tony Blair continues to invest great weight in his estimation of what is best for Tony Blair". The Prime Minister apparently once said that if a third World War broke out he would first ring Peter because he would offer advice "with a coolness, clarity and acuteness" unmatched by anyone else he knew.
Closeted in the pre-election bunker, drawing ever closer to that "loneliest" decision, it seems Mr Blair was true to his assessment of the former sultan of spin, consulting Mr Mandelson two or three times a day on the hotline.
"It really is incredible," confirms another close observer of the New Labour scene. "Peter does rise from the dead more often than Dracula."
Indeed, as Easter approaches, this political resurrection has stunned many at Westminster who cheered Mr Mandelson's descent into outer darkness, to the background noise of Mr Blair's spokesman questioning his sanity and cheerful predictions that he might even stand down as an MP before the good people of Hartlepool had the chance to dump him.
But there should perhaps be no surprise. Whether or not spun by Mr Mandelson, there was good reason to note one early report casting Mr Blair as increasingly isolated in a cabinet in which the Chancellor, Gordon Brown, was said to be "rampant".
Crucially, the report identified Mr Blair's fear that the loss of Mr Mandelson could endanger New Labour's modernising project. Mr Mandelson subsequently raised himself above the parapet to warn against any temptation to return Labour to class or tribal-based politics.
And it was probably fidelity to the project which ensured Mr Mandelson's victory over those urging the Prime Minister to proceed on May 3rd.
As that keen observer explains: "Blair would have been receptive to the `One Nation' argument. He knows it makes no difference to the outcome, he's still going to win on the June 7th. But he would be more worried about how he would govern after that if he'd alienated large parts of the country in the way Thatcher did. That's not the Third Way."
But the result, he ventures, is potentially very damaging for the Labour Party, "not least because it seems clear that Blair values Mandelson's advice over that of Alistair Campbell". Pre-resignation mention of Mr Mandelson immediately opened up questions of Blair/Brown, Blair/Mandelson and Mandel
son/Brown. To which now may be added Mandelson/Campbell. It is not clear to what extent Mr Mandelson holds the Prime Minister's official spokesman responsible for his summary dismissal from the cabinet. But Mr Campbell will hardly be thrilled by suggestions that Mr Mandelson now thinks himself secure as "the most important unofficial influence behind Mr Blair in a second term in office". Mr Blair likes to dismiss all such talk about New Labour's personality battles as so much froth. He may expect plenty more of it.