I often read hugely hyped front page stories and ask myself “why?” But the Mail on Sunday’s great scoop yesterday, “Two Eds hid truth about global crash”, left me scratching my head all day.

Why, why, why? It was based on the serialisation of a book that doesn’t appear on any publishing list by a man we’ve never heard of about supposed events that everyone connected to his allegations disputes.

I accept that the 300,000 good citizens of Doncaster may recall that Martin Winter was their mayor for seven years from 2002. They may also remember that he was Britain’s first elected mayor and that he stood for Labour.

It is also possible that they recall Winter being a supporter of Labour’s leader, Ed Miliband, who won the Doncaster North seat at the May 2005 general election.

Some will undoubtedly recollect that Winter later declared himself to be an independent and was expelled from the Labour party. His administration then ended in controversy, acrimony and something of a farce (see his Wikipedia entry here).

Winter’s political about-turn made hardly a ripple outside Doncaster. His disappearance from the mayoral chair in 2009 passed without any national comment and nothing, unsurprisingly, has been heard of Winter since.

Nor, indeed, did he think to write his “book” closer to the events he claims to have witnessed. The timing of his decision to write it is obviously significant.

Yet the MoS thought the story told by this political nonentity, with obvious axes to grind against the party that he turned his back on seven years ago, worthy of a splash, five more pages inside plus a leading article.

The paper clearly regarded Winter as a kingmaker, the man tasked by the former prime minister, Gordon Brown, to ensure Miliband secured the safe Doncaster North parliamentary seat.

It obviously believes his story has validity because he spent nine or so weeks living with Miliband and therefore has insights into the Labour leader’s personality.

But I couldn’t help but notice that Winter’s tale was tricked out with popular newspaper journalese. It was “sensationally revealed last night” that he was making “bombshell” claims in “an explosive new report” that added up to “a devastating indictment” of Miliband.

I have a lot of time for the MoS’s political editor, Simon Walters, but it was sad to see his byline on this confection of unsupported allegations and pathetic innuendo. He is better than that.

Doubtless, some Labour party politicians will view the exercise ahead of the coming election as something of a smear. But it was such a damp squib that it got almost no broadcasting coverage and few follow-ups in the rest of the press, with the exception of today’s Sun (a nasty page lead plus a nastier leading article) and a passing reference in Boris Johnson’s Daily Telegraph column.

Winter’s central allegation – that Miliband and Ed Balls urged Brown, to call a snap election in 2007 because “the economy was about to fall off a cliff” and it was Labour’s only hope of holding on to power – has been comprehensively denied.

Does anyone seriously believe that Miliband and Balls, unlike the rest of the financial and political world, foresaw the 2008 banking crisis and economic crash?

The rest is an attempt at a character assassination of “Calamity Ed” Miliband, casting him as a Mr Bean figure replete with uncheckable tittle-tattle.

It is fair to point out that Miliband’s press office didn’t handle the Mail on Sunday’s initial contact competently. Instead of responding with a straightforward denial (now belatedly issued), it described the allegations as “ancient history”.

In reporting parlance, the MoS may well have viewed that comment as a non-denial denial, meaning that the story was broadly true. Even so, I remain sceptical about the credibility of publishing such a story.

I note that my colleague, Josh Halliday, found an MoS executive who thought Winter’s discontent “good stuff” and “entertaining”. I’m not sure that those are well-founded criteria for personal attacks on a political leader.

The MoS editorial accepted Winter’s portrayal of Miliband as an other-worldly Hampstead intellectual who is accident-prone, clumsy and awkward with children.

Its central message was that Miliband’s alleged inside knowledge of, and concealment of, the 2008 crash “reignites David Cameron’s case that Labour simply is not fit to be trusted with the economy”. Really?

Evidently, Winter’s book, entitled Fallout: the man who made Ed Miliband an MP, will go on sale in April. I can’t see a record of it anywhere, although I’m given to understand that he has written a manuscript of 100,000 words. And there is set to be more next week. I can wait…