I pentiti is the name for Mafia turn-coats. Members of Cosa Nostra all their lives, the pentiti (Italian for penitents) usually see the light only when they're in trouble. Behind bars, interrogated and threatened with a life sentence, they suddenly find themselves ripe for conversion. Repentance wins them a lighter sentence (sometimes freedom) and loads of publicity.
The penitent Tory follows a similar trajectory. Once a paid-up member of the Conservative clan - rooted in the Home Counties rather than Sicily, but with a moral code no less ingrained than omerta - he comes up against a little local difficulty. This may be perjury, outing as a former gay or a bit of plotting against the party leader. The penitent Tory submits to public humiliation with a set jaw and grim expression - and then capitalises on the crisis by undergoing a transformation that wins him plaudits, publicity and the sympathy of even former foes.
Look at Jonathan Aitken: indicted for perjury, he spent seven months in Belmarsh and Standford Hill prisons. There, the former liar, playboy and renegade underwent a Damascene conversion and became a happy-clappy Christian. His very public mea culpas - a succession of chest-beating articles appeared in the Tory press - earned him a new wife, the sympathy of Alpha course addicts and, gradually, of 200 members of his former constituency party, Thanet South.
Look, too, at Michael Portillo. After failing to oust William Hague as party leader and admitting to having had gay sex as a young man, he abruptly dropped his former SAS-loving, gung-ho image to adopt a softer, humble, penitent persona. The new Portillo opted out of the parliamentary snake-pit to star in a series of soft-edged telly programmes, most conspicuously his recent visit (camera crew in tow) to a sink estate where he winsomely shared the pain of being a hard-up single mum. It worked: his bonding with his difficult teenage "daughter" had even cynics feeling bat-squeaks of sympathy.
The sackcloth and ashes didn't end there. As the NS's new theatre critic, he reviewed David Hare's play about rail privatisation, The Permanent Way, last week - and admitted that watching it as a former transport minister, he had had difficulty swallowing.
Who can resist such heartfelt repentance? We've taken the former bad-boy Conservatives to our bosom, giving Aitken hope for a second bite at the cherry and Portillo his own dinner parties on BBC4. The liberal chattering classes see in these converts a delicious vindication of their own world-view. Old-school Thatcherite Tories have gone into moral bankruptcy; only those who re-emerge as caring and sharing Conservatives can regain their credit rating with the public.
But the penitent Tory does not merely reassure the bien-pensants that theirs is the right way. He also highlights the failure of new Labour's bad boys to say "sorry". An Aitken or a Portillo puts to shame the likes of Alastair Campbell and Peter Mandelson, who storm out of public life in a blaze of acrimony and pursue vendettas from their cold and distant outposts. Who can forget or forgive Mandelson's triumphalist cry when he won back his parliamentary seat, or Campbell's strutting about the BBC studios post Hutton? No sign of remorse, no talk of regrets, no plea for our forgiveness. A mistake: their unrepentant attitude dooms them to a twilight world where they risk languishing, their influence forgotten, their advice unheeded. Even a mafioso knows better.