Matthew Norman: This amoral and repugnant regime

Another week in which the British government has ridiculed and degraded itself draws to a close

In any compendium of New Labour turncoats, a little space would be required for Chris Mullin. In truth, the member for Sunderland South isn't a major player in this league, mirroring his constituency football club by floundering at the bottom of the Premiership, far below such titans of turncoatery as "Dr" John Reid, the erstwhile communist whose wife purchased a house via that great emblem of Marxist-Leninist orthodoxy, the offshore trust. But Mr Mullin deserves at least a footnote for a betrayal of a cause he once represented with distinction.

This week, on the 30th anniversary of his resignation, the security service conspiracy to remove Harold Wilson from office has come to seem even less a theory and more a plain fact than ever before. Not that Mr Mullin ever had the remotest doubt, embellishing on the plot against Wilson for the plot of his 1982 novel A Very British Coup. His Yorkshireman Prime Minister Harry Perkins came from Sheffield rather than Huddersfield, and in so far as he was a version of Wilson at all he was an intensely idealised one. But the fundamental premise was the same: MI5, or some of its more dementedly paranoid operatives, conspired to frame, destroy and remove by coup d'état an elected leader they absurdly believed to be a Trojan Horse for the sort of Soviet takeover about which the pre-offshore trust "Dr" Reid might once fondly have fantasised.

A Very British Coup is a fine book (and an even better TV drama), and when I met Mr Mullin at a party a few years ago I gushed my admiration. Then I asked how the man who wrote this searing exposition of the sinister unaccountability of our security services could, as the Foreign Office minister he then was, defend the limitless detention of British citizens in Guantanamo Bay, often solely on the unreliable word of those same intelligence services?

I'd had a few and was doubtless mildly offensive, and understandably he backed away, but I persisted with the semi-drunken rant until he came out with a line that still echoes in my head in that effete patrician lisp of his. "What you have to understand," declared this once revered investigative journalist and warrior on behalf of victims of injustice, "is that these are bad men."

Ah, so that's it, I mumbled. We needn't bother with such quaint, outmoded fripperies as evidence. All it takes for a chap to be banged up in an orange jump suit with no prospect of a trial is for someone like you to declare him a bad man on the say so of the security services about whose inherent untrustworthiness you yourself are an acknowledged expert.

He'd left my company long before the end of the rant, and to his credit he left the Government after the last election, joining backbench rebels in defeating the proposal to increase the maximum detention period for terrorist suspects to 90 days. Even so, I wonder what Mr Mullin felt when he read the report by their lawyer George B Mickum in yesterday's Independent about the two men - British residents rather than citizens, but still entitled to this country's protection - whose reward for helping MI5 officers in counter-terrorism was to be handed over by them to the CIA, and held in Guantanamo to this day with not one shred of evidence against them.

Even by the time-honoured standards of perfidious Albion, this is a betrayal that makes you want first to weep with impotent rage, and then inflict the sort of torture on those responsible that Bisher al-Rawi and Jamil el-Banna have suffered at the brutal hands of their American hosts.

Asked about the matter at his news conference yesterday, the Prime Minister was careful to strike a mealy-mouthed note of judicious impartiality - and we may draw our own inferences from his refusal to deploy the blanket denial that is the traditional New Labour auto-response to any serious allegation against it. The general rule, indeed, is that the graver and more indisputable the charge, the swifter and more categorical the denial.

In the last two days, we have been treated to two classic examples of a political genre whose origins remain the subject of heated academic debate. Some believe the tactic to be modelled on It Wasn't Me, the rapper and former US Marine Shaggy's hit single about a young man who, caught in delicto with a neighbour by his girlfriend, stoutly maintains his innocence.

"Picture this, we were both butt-naked/ Banging on the bathroom floor," goes one verse, "I had tried to keep her from what she was about to see/ Why should she believe me when I told her it wasn't me?"

Why indeed? Yet despite recognising the futility of the lie, Shaggy can't help himself. "But she caught me on the counter (It wasn't me)/ Saw me banging on the sofa (It wasn't me)/ I even had her in the shower (It wasn't me)/ She even caught me on camera (It wasn't me) ..." and so on.

The alternative source posited by rival experts is the Simpsons episode "Bart Gets Famous", in which, after screwing up his only line in a live TV sketch he's performing with Krusty the Klown, Bart blurts out "I didn't do it!" So hilariously pointless is the denial that it brings the house down, Bart instantly becomes a star, and "I didn't do it" a national catchphrase.

Which of the two was the role model for Jack Straw and Charles Clarke we may never know, but these two Kabinet Klowns would have made Bart and Shaggy proud of them this week. First Mr Straw said it wasn't he who colluded with Israel, whose troops arrived to storm the prison in Jericho within minutes of Britain withdrawing its monitors. Then Mr Clarke insisted that New Labour didn't do it regarding the flogging of peerages - a denial reiterated a few hours later by the Prime Minister at the same news conference at which he failed to dismiss Mr Mickum's claims about his clients with the usual glib finality.

And so another week in which the British government has ridiculed and degraded itself in equal measure draws to a weary close, with Mr Blair declining to criticise the security services which conspired to commit treason against a predecessor decades ago for a more recent act of treachery against two men from whom "I didn't do it" appears, for once, to be the literal truth.

How as fundamentally well-meaning a man as Chris Mullin ever allowed himself to be tainted by association with such a repugnant and amoral regime one can only guess (probably the old, old story; one intoxicating sniff of red box, and he was anyone's). But it would be comforting to imagine he lost a little sleep last night pondering the unpardonable betrayal of two innocents by the the security services he used to attack and the government in which he was naive enough to serve.