EVERYONE HAS been quoting Enoch Powell’s famous maxim that “all political careers end in failure” since Tony Blair’s disastrous Cabinet reshuffle, a danse macabre that will be remembered as the most confused suicide pact in history.

If there was one thing Mr Blair was even more determined to do in his final year than democratise Iraq, rebuild the NHS and eliminate poverty in Africa, it was to be the first Prime Minister in history to escape the Prophecy of Enoch. Now he has failed. This is hardly surprising, since Mr Blair’s attempts to ward off the prophet’s dire tidings were as fatefully misguided as Macbeth’s decision to make his last stand on Dunsinane Hill.

One can only wonder what strange unseen powers may have guided Macblair to bathe in the reeking wounds of Jack Straw, Charles Clarke and other trusty retainers. Was he hypnotised by a vision spun out of thin air by the weird brothers, Mandelson, Campbell and Gould? Or was the Prime Minister driven to this murderous madness by the vaulting ambition and paranoid noctural ravings of Lady Macblair?

Since everyone now agrees that Mr Blair’s career will end in failure, the next question worth asking is what dramatic device might bring his increasingly tedious tragi-comedy to a swifter than expected conclusion. To answer this question, let me introduce yet another cliché (usually attributed to Mark Twain): “History does not repeat itself, but it rhymes.”

The last days of Mr Blair will not, of course, turn into an exact repeat of the last days of Margaret Thatcher, but uncanny parallels have started appearing in the rhythm and meter of the two dramas. Many have observed the obvious similarities, such as the role of sycophantic courtiers in isolating the Prime Minister from his Cabinet and the public. But last week’s botched reshuffle created some much more specific analogies that nobody would have imagined even the day before.

Perhaps the most intriguing is that the Prime Minister’s survival again depends entirely on a former Foreign Secretary who has been needlessly humiliated and demoted. Just as it was the resignation speech of Sir Geoffrey Howe that triggered the coup against Mrs Thatcher, we now see Mr Blair’s career hanging by a thread that Jack Straw can cut with a single word at any time.

Mr Straw is the only man who knows the full truth about the preparations for war in Iraq, about the contingency planning for striking Iran and, above all, about the Blair-Bush relationship. If he were to reveal what he knows, Mr Blair’s career would be over in a moment. I am not suggesting that Mr Straw would do this as an act of petty personal vengeance, but rather as a principled service to the security of the nation and the survival of the Labour Government, following the precedent set by Sir Geoffrey when he denounced the erratic, arrogant conduct of European policy under Mrs Thatcher, thereby precipitating her demise. The possible catalysts for such an outburst by Mr Straw are easy to imagine; a hint of military action against Iran from the new Foreign Secretary; some egregious calamity in Baghdad or Basra; maybe just a sabre-rattling speech from the Pentagon or the White House, over-zealously endorsed by Mr Blair.

A similar argument applies to the other principal victim of Mr Blair’s ministerial massacre last Friday.Charles Clarke could be almost as dangerous an enemy as Mr Straw, and he now enjoys the freedom of the back benches. Suppose the former Home Secretary were to tell the full truth about his struggles to restrain Mr Blair’s authoritarian instincts — on identity cards, on extra-judicial detention and on the whole panoply of anti-terror laws. Like Sir Geoffrey, Mr Clarke could justify such an exposé as a way of clearing his own reputation and protect the nation against some new excess from Downing Street. Could anyone imagine Mr Blair surviving such a broadside from Mr Clarke?

Now consider what the rhymes of history may be whispering to Mr Brown. One surprising lesson of history is that a long and messy prime ministerial demise may actually help his successor. The longer Mr Blair spins out his death throes, the more his successor will be seen as a liberator and saviour. If Mr Blair becomes so peevish and arrogant that his removal is greeted with national jubilation, Mr Brown, just like John Major, can expect a happy honeymoon. He can also expect a further advantage because of the electoral strategy chosen by David Cameron. Mr Cameron is under the strange illusion that Mr Brown is feared and loathed by Middle England, while Mr Blair is trusted and adored. Thus Mr Cameron has decided to present himself as Tony Blair’s natural heir; as things are going, he might do better to trace his lineage to Attila the Hun.

But the key lesson of history for Mr Brown concerns the steps he must take to avoid the long-term fate of John Major: to do this he must immediately ditch the Blairite policies most responsible for the present Government’s demise. Mr Blair’s equivalent of poll tax may be legislation on ID cards or hospital reforms, but the policy at the heart of Mr Blair’s failure — the equivalent of the rows and misjudgments over ERM membership under Margaret Thatcher and then under John Major — is Mr Blair’s relationship with the Bush Administration and his policy on Iraq.

By pulling out of Iraq and breaking publicly with the Bush Administration (which by then will itself be in terminal decline), Mr Brown could win himself so much credit with the Labour Party and the affluent middle classes that he could do almost anything else he might choose with the health service, taxes, pensions or schools. Mr Major’s fate was sealed by the way he stuck to a policy that was doomed to failure — membership of the ERM.

If Mr Brown heeds the rhymes of history, he will ditch the foreign policy that has been responsible for Mr Blair’s demise. If he does this, he could yet turn a funeral dirge into a song of triumph.

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