I bet there'd be no point gossiping personally to Gordon Brown. He'd grunt and go back to his economic treatise or virtuous tale of British heroism. It is hard to see how such a rugged rock got furred with exotic growths - Mandelson, McBride, Draper - unless you surmise that he inherited a nasty fungus from Tony Blair and never got round to wielding the bleach. He'll wish he had, now: despite Damian McBride's resignation, his boss is irrevocably damaged by the revelation that his “head of strategy and planning” is a social disease in his own right.

If you had more uplifting things to do on Easter Sunday than study Mr McBride's e-mails, they consist of one possibly “solid” story about an MP's partner's business, and several others which even to the author are rife with “poetic licence... gossipy and mainly intended to destabilise the Tories”. The first is to suggest that David Cameron is having private treatment for an embarrassing sexually transmitted disease and demanding his “full financial and medical records”. The second refers to (imaginary) photos of the Shadow Chancellor posing in a bra and suspenders and “with his face blacked up”. Mr McBride has seen no such photos, but speculates hopefully that “he wouldn't be the first student to do some cross-dressing at university...” The third and fourth are about women. One says “friends” worry about George Osborne's wife, based on a picture of her failing to smile full-time in public. The fourth is a concocted tale about a woman backbencher, and is explicitly and nastily sexual. No need to draw pictures. She is threatening to sue, and good luck to her.

Derek Draper, the recipient, jibs at the idea that he shares the blame, yet on receiving this drivelling tosh he wrote back: “Absolutely totally brilliant, Damian... I'll think about timing and sort out the technology.” He blusters that the police should investigate the leak (interesting if they were to invoke the laws on defamation while they were at it). Draper also defends the whole exercise as mere draft plans, “banter between blokes” and no more than “a bit juvenile and inappropriate... but ... brilliant and rather funny”.

Yeah, right. Only in the age of Jonathan Ross and Russell Brand, whose Andrew Sachs call was initially thought “v. funny” by BBC executives.

But be serious. These planned smears emerged from a Downing Street e-mail account (what kind of twit doesn't even set up a Hotmail identity?) and from a paid civil servant. They were revealed by the somewhat smug “Guido Fawkes” political blog written by Paul Staines, which Draper was hoping to counter from a Labour standpoint. Apparently everyone involved in these political bloggeroos hates everyone else, but leave that to the Westminster-watchers, I don't care. What interests me is the whole question of gossip and smear, and why a Prime Minister's office would use it.

Gossip is a human foible, and Christianity has long identified it as a sin (Penny Catechism, Q221-222 - “Calumny and detraction, tale-bearing and any words which injure our neighbour's character... If I have injured my neighbour by speaking ill of him, I am bound to make him satisfaction by restoring his good name as far as I can”). Some is less toxic, some more. If it is true, gossip can be useful and protective: some characters really should carry an advance warning. But true or false, it is compelling: people like stories. As Roosevelt's maverick daughter Alice observed: “If you haven't got anything nice to say about anybody, come sit next to me.”

But in private discourse gossip is put in its place. It is malicious when it affects a real acquaintance, but wild talk of public figures can be oddly harmless. When someone informs you at supper that the Salvation Army is secretly funded by Silvio Berlusconi, that MI5 killed Jade Goody because she knew too much, that Michelle Obama is a crack user whose supplier is the Duke of Edinburgh (so that's why they came to the palace! It all fits!), and that a “Vatican insider” knows for sure that the past ten Popes have all been practising gays except possibly for John XXIII, you smile and say: “Is that so?” Or just snort, and revise your view of the informant accordingly. But perhaps not too severely: he was only trying to entertain.

It is when gossip is scientifically disseminated to “destabilise” people in a serious arena that you really catch the whiff of sulphur. There is a long history of this: in the 1980s appalling and unfounded sexual stories were circulated about the Home Secretary, Leon Brittan, and more or less proved to emanate from MI5 officers who resented political interference (there are more recent likely examples from that quarter, but never mind that).

During the David Kelly affair the dead scientist was unforgivably described as a “Walter Mitty” character by a Downing Street aide. In the US election anonymous e-mails told voters in South Carolina that Hillary Clinton was having a lesbian affair, that Rudy Giuliani's wife killed “innocent puppies”, and conversely that McCain's wife was an addict and he had a black love-child. This is apparently known as “stripping the bark off 'em”.

Well, Britain is not South Carolina, but we're getting there. In one council election a gay candidate with an Asian partner - aged 39 - found rumours circulating that this was a “14-year-old Thai boy”. An opponent half-admits starting this. Smearers rely on the “no smoke without fire” belief, and this is the deep evil: that you can no more call back the whole of the rumour than you can unring a bell.

They also rely on an unfortunate thread of our national history, for which bygone Establishment figures bear heavy responsibility. One reason we are so credulous now, such ready blog-believers, is that in the past the lid was kept on far too tightly.

Britain was the last country to be told about Wallis Simpson, who lost us a King. Not until years afterwards did our press dare to make us aware that Lord Boothby was sleeping with both the Prime Minister's wife and with Ronnie Kray, with offshoots of their liaison bringing in Tom Driberg, himself a close friend of the spy Guy Burgess...

No wonder we are now such fertile soil in which to plant McBrideian lies. No wonder politicians are tempted to fling random dirt. But it's still disgusting. And why, incidentally, was it a resignation and not a public, explicit sacking?

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