Mandelson turns the screw in new Labour's Medici court

The sound of Pavarotti being squeezed till his pips squeak bears little resemblance to the tenor's honey-toned arias.

Not-so-lucky Luciano has rejected his estranged wife's claim for a £70-million divorce settlement. Adua Pavarotti's revenge is to join forces with the Italian taxman, and now her husband of 35 years faces the possibility of criminal charges. Adua is bound to know where all the fat man's skeletons are buried; and after being thrown over for a woman half her age, the scorned wife is ready to hit the man where it hurts.

Who could fail to sympathise? After so many years of unflagging devotion, is betrayal Adua's only reward? Rather than instantly vent her venom on her faithless husband - cutting off his manhood a la Lorena Bobbitt, or organising an honour killing, Mafia-style - Signora Pavarotti has lived by the proverb, "revenge is a dish best served cold". Hence her Machiavellian machinations with the taxman. Forget turn the other cheek, this is the turn of the screw.

Don't let anyone brush off Adua's vendetta as particular to Italian womanhood or to marital breakdown: the ex-wife's conduct offers a striking personal parallel to the vengeful goings-on in the political arena over here.

Tales of revenge (allegiances rendered and betrayals avenged) have always provided a dark leitmotiv to life at Westminster and Whitehall. Never more than now, though, when - under the aegis of new Labour - the political scene has turned into an Anglo-Saxon model of the Medici court or the Pavarotti household. And behind every plot, his hand holding the stiletto, lurks the shadowy figure of an eminence grise whose extraordinary influence at No 10 must be defended at all costs. Among courtiers, revenge stories about Peter Mandelson abound. Perhaps they are more parliamentary folklore than truths, but the allegations include leaks to, and smears in, newspapers; whispers into Tony's ear; the calling in of favours; the holding out of promises . . . the vendettas are carefully orchestrated campaigns that, in their schemer's mind, right the wrong and straighten out the crooked.

Those who see Mandy as vendetta-driven rely on plenty of anecdotal evidence. Think, they say, of what happened to Charlie Whelan when Mandelson fell from grace as a result of revelations about his home loan: Charlie, suspected of having had a hand in Peter's public humiliation, lost his post as Gordon Brown's press secretary and was banished to outer darkness - or at least to appearances on Have I Got News for You and the compilation of the racing card in the New Statesman. Think of what happened to Mo Mowlam. The long-time Mandelson foe was turfed out of Northern Ireland and stripped of her right to bodyguards - all at break-neck speed. And what of the fate of our chairman, Geoffrey Robinson, who was embroiled, like Whelan, in the home-loan fiasco? Some gossips have seen Mandelson's hand behind the spate of allegations about Robinson's business deals.

Like Adua, Mandelson's vindictive streak is all the more formidable for being fed on a great love under threat. His loyalty to Tony is unparalleled, his love of the party undisputed, his self-righteousness unbound. Hence his unbridled fury at anyone perceived as a threat to this trinity. You have failed to stay on message? You're banned from the project! You have not shown enough reverence in your dealings with the leader? You're sacked! It's vicious, it's dirty and it's instinctive, as much as with any Mafia don or spurned wife. But it's also carefully planned and cleverly executed, boasting the wily precision of The Prince.

So beware, Ken Livingstone. You're next: you've besmirched Tony's honour, raised two fingers at the party, blasphemed against the cause. Someone's plotting revenge even as we speak; and it may be served cold - but they'll make sure it's deadly.