To lose the support of liberal-minded voters in the south might be considered a misfortune. To lose working-class support in the north looks like sheer carelessness. But to lose the Glasgow East by-election next week would be a personal disaster. That is the prospect facing Gordon Brown. He looks as friendless as Heathcliff, the brooding anti-hero of Wuthering Heights to whom he has acknowledged an affinity.

All the great parties are coalitions of interests, classes and regions. The libertarian tendency is balanced by the authoritarian, north by south, working class by middle class. Labour’s coalition is fracturing. A few years ago in his book The Strange Death of Tory England, the Conservative writer Geoffrey Wheatcroft warned that his tribe was becoming the partyof the south minusthe capital. Margaret Thatcher had won the battles over the market, the trade unions and the economy, leaving the Tories with nothing left to say except “Yah boo” to Brussels. Tony Blair was happy to manage her inheritance.

Now it is Brown who seems to have little to say, as the Tories promise to build on Blair’s tentative reforms of the public services. David Cameron boldly addresses “the broken society”, just as Blair once promised to tackle the causes of underclass crime. What’s the prime minister’s message for these troubled times?

Labour likewise is retreating to its industrial heartlands. The local elections wiped out the party in the south, London too, while the Crewe by-election saw the party crumbling in the north. If the Scottish nationalists come close to taking hitherto impregnable Glasgow East, Wheatcroft will have to start pounding out a new book, The Strange Death of Labour Britain.

Optimists among Labour MPs believe that a successful coup against Brown would still allow the party to put up a strong showing at the next general election. The pessimists glumly fear that the party’s time in government is up: regicide would only make matters worse. A wavering group in between hopes against hope that a change of mission not personnel will revive the government.

It is striking that the old bag of tricks isn’t working any more. Brown’s favourite party piece is the so-called “wedge issue” that divides the Tories from their natural supporters in the electorate. But nowadays the wedge drives his core small-“l” liberal support ever further away from Labour.

The prime minister, for instance, must have thought he was onto a winner with his proposal to lock up terrorist suspects for up to 42 days without charge. The Tories are historically the party of law and order, but they think this curtailment of civil liberties is so far unwarranted by the facts. On first sight, the majority of voters vehemently disagree with the Tories and side with Brown: do whatever it takes to stop the bombers. A perfect wedge, you’d have thought.

Yes, it has made some mischief between the former Conservative shadow home secretary, David Davis, and his leader after he called a by-election on the issue, but it didn’t divide the party from its natural supporters. The Tory maverick’s constituents may not share his views but they have a grudging respect for a man who sticks by his guns and sent him back to the Commons. The turnout in Haltemprice and Howden was not humiliatingly low, despite the absence of Labour and Liberal Democrat candidates.

Meanwhile Brown hasn’t convinced the floating middle that his arguments are equally sincere or authentic. Labour’s middle-class, southern supporters are horrified by the whole episode. Even “Saint” Bob Geldof, Brown’s ally on African debt relief, has, in The Daily Telegraph of all places, berated the new authoritarianism . The coup de grâce, however, was delivered by a pillar ofthe establishment, Dame Eliza Manningham-Buller, the former head of MI5. She attacked 42 days in her maiden House of Lords speech. When a Judi Dench-like “M” figure drives the poisoned stiletto home, you know your case is doomed.

A still ambitious cabinet minister was telling me the other day that the slogan “British jobs for British workers” had been a surefire hit with every focus group. Thus market-tested, Brown proudly launched it in his first Labour party conference speech as leader. After he repeated the pledge, Brown’s former liberal friends in the press poured a great big bucket of manure over his head. Many compared the slogan with British National party propaganda. One Labour MP called it a recipe for “employment apartheid”. Another wedge, another loss of liberal support.

And where is Brown’s core message? Others have mocked Brown’s war on waste conducted from the champagne and caviar tables of the G8 summit, but his silence on knife crime is more telling. While murder and mayhem dominated the news, it took a fortnight for the prime minister to issue a brief statement. Even now he hasn’t made a single speech about law and order. That wins him no friends at Islington’s sharp white dinner tables. Labour’s metropolitan supporters fret about the safety of their children on the mean streets as much any Tory mum or dad.

Blair could call on the formidable services of Jack Straw, David Blunkett, Charles Clarke and John Reid to fight his corner on law and order. Jacqui Smith, the home secretary, has large hobnailed boots to fill.

Brown has little to say about rising food prices and the price of petrol too. Though he has tried to feel our pain, no phrases of his have been memorable. His proposed rise in vehicle excise duty that will hit 9m motorists, however, won’t be forgotten if it survives a backbench revolt.

The polls provide further evidence that the electorate has firmly made up its mind about the prime minister – on a Populus “leader index” he has dropped below the previous record low, achieved five years ago by the hapless Iain Duncan Smith. The Sunday Times/YouGov poll today says the voters think he is not Heathcliff but vindictive and bloody Macbeth. The Scottish play, you will remember, is Shakespeare’s shortest tragedy, but this production looks protracted.

Labour waverers advise waiting on the Glasgow East by-election. Or perhaps the polls will improve by the end of summer. After the Conservative party conference is the best time to make up your mind: Christmas is even better. MPs mutter that it’s up to party veterans such as Straw, Alan Johnson, the health secretary, and Geoff Hoon, the chief whip, to tell the prime minister to go. “You don’t get the red boxes and the Jaguar for free: you have to lead,” says an influential opponent of the prime minister, who forgets that ministers now get to swank in a green Toyota Prius.

It is a risk to force him out, it is a risk to have a leadership contest, wail other Labour stalwarts. To which one dissident mordantly replies: “there is no element of risk to keeping Gordon, the outcome is certain. It is disaster”.

Others counter that Labour’s defeat is certain anyway. But history’s lessons are otherwise. Yes, Labour prime minister James Callaghan lost the 1979 election to Thatcher after he took Harold Wilson’s place in 1976. But had he not delayed an election until after the winter of discontent, when striking grave diggers left the dead unburied, he might have won. John Major pulled the Conservative party back from the brink after Thatcher’s poll tax debacle and went on to win the 1992 election.

Another Labour dissident warns that the parliamentary Labour party is like a suburban house owner who has got to the end of his tether with a nuisance neighbour. He keeps calling the police but the authorities either tell him their hands are tied or won’t act. “People will take the law into their own hands soon,” he adds.

In the case of Labour backbenchers, if the cabinet won’t move, they could back a stalking-horse candidate, which really would show a party divided. That would mean round-robin letters, PPSs resigning, junior ministers walking and more big votes lost in the Commons.

Yet a stalking horse hasn’t emerged. The only MP tough enough to contemplate such a course, Brown’s outspoken critic Charles Clarke, found he could not rally enough support in the parliamentary party to mount an effective challenge.

If Brown is Macbeth, then his parliamentary party is divided about how to get rid of the usurper. His enemies urge, “Lay on, Macduff”, but no Macduff appears. Nobody demands, “Infirm of purpose! Give me the daggers”. Meanwhile Labour’s support silently fritters away.

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