Leading article: This is not a plot. It is a groundswell of discontent

The first big beast in the Labour jungle has roared for the Prime Minister's head. Charles Clarke, the former Home Secretary, yesterday called on Gordon Brown to "stand down with honour", unless he is able to resurrect the Government's popularity over the coming few months.

Mr Clarke claims to believe that a turnaround is "entirely possible" but the fact that he has delivered his ultimatum in the middle of Mr Brown's economic "re-launch" suggests that, in truth, he thinks the game is up for the Prime Minister. Otherwise, Mr Clarke would surely have waited to see if Mr Brown's new mortgage support package and next week's promise of help for those in fuel poverty would ease the pressure. In Glasgow last night, the Prime Minister's speech on the economy was entirely overshadowed.

It gets worse for Mr Brown. Mr Clarke's intervention is not just a plea but also a threat. In Mr Clarke's view, Labour is "destined to disaster if we go on as we are" and warns the Prime Minister that "we will not permit that to happen". In other words, unless Mr Brown goes of his own accord, he faces the prospect of being forced from Downing Street. It makes for a pretty brutal intervention, even by Mr Clarke's usual robust standards.

If there is a crumb of comfort for Downing Street, it is the fact that Mr Clarke's broadside does not seem to be part of an organised plot to unseat Mr Brown. Mr Clarke's intention in breaking cover seems to be to encourage members of the Cabinet to follow his lead. The Prime Minister, therefore, has a chance to counter the attack by presenting Mr Clarke as a disloyal maverick, something that the Children's Secretary, Ed Balls, set about doing with some energy yesterday. And everyone knows there is no love lost between Mr Clarke and Mr Brown. Mr Clarke was one of the few Labour MPs who resisted the former Chancellor's elevation to party leader last year.

But portraying Mr Clarke as a bitter voice in the wilderness will not be easy. The former Home Secretary does not speak for Labour, but he is articulating a widespread concern within the party about the quality of its leadership. And this concern will grow as the next election draws nearer and Labour MPs become increasingly concerned about their seats.

Yet there is an omission in Mr Clarke's analysis of the plight of the Government this week: any proposal of alternative policies. The Government's problem is not merely the personality of its leader. Certainly, Mr Brown's inability to articulate Labour's policy goals and generate popular enthusiasm for them is a terrible liability. But the reality is that the Government's problems are much more than issues of presentation.

They are intimately connected with the squeeze on the cost of living resulting from rising inflation; the popular feeling that public services are still not delivering value for money despite record investment; the growing anxiety about the state of the economy. They lie, too, in the general air of tiredness that hangs over this administration after more than a decade in office.

Mr Clarke might be right to infer that a new leader would boost the Government's popularity. But whoever took over from Mr Brown would still be faced with precisely the same dire economic conditions. It is all very well for the likes of Mr Clarke to urge the removal of Mr Brown, but the party's MPs and members should also give serious thought to what policies might prevent them being dashed to pieces on the rocks of the next election. Dropping the captain is unlikely to be enough.

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