Leading article: These are dangerous times for the Labour Party

How the Prime Minister must now regret announcing his decision to step down before the next general election. Tony Blair claims he did not want to be accused of "going on and on" like Margaret Thatcher. But the situation he has contrived for himself is far worse. The Prime Minister is now under enormous pressure to name the date on which he will leave Downing Street. And despite a vigorous effort to neutralise the issue at his monthly press conference yesterday, the pressure is certain to continue. Everyone is aware that the clock is ticking on the Blair era.

This is no media-concocted firestorm. It is Mr Blair's own MPs who are leading the calls for the Prime Minister to clarify his plans. Fifty backbench Labour MPs are reportedly ready to sign a letter calling for Mr Blair to name a departure date within the next three months. Gordon Brown, the man widely expected to be elected as his successor, has done nothing to discourage this. The Chancellor's own language on the anticipated "handover" is becoming increasingly pointed as his frustration grows. In an interview over the weekend he spoke of the need for Labour to "renew" itself in office. In fact, Mr Brown used this word 25 times in 20 minutes. His meaning was obvious: it is time for Mr Blair to go. And the fact that a number of Mr Brown's allies in Parliament have now called for Mr Blair to "name the day" only confirms that divisions are growing wider.

The call for a "handover timetable" from the Prime Minister is ridiculous, however. This would only make him even more of a lame duck than he is at present. And for all Mr Blair's many failings as Prime Minister, he is justified in pointing out that only a year ago he led the Labour Party to a third straight general election victory, renewing his mandate from the British people. Mr Blair is also right to draw attention to the motives of some of the more extreme Labour rebels. One of their primary objections to Mr Blair's continuation in office is his "commercialisation of the public services". There is, as Mr Blair's outriders point out, a hint of Old Labour revanchism about such outbursts.

The invasion of Iraq is unquestionably the greatest item on the charge sheet against Mr Blair, one that lost him the trust of vast swathes of his party and the public. That mistrust endures. Labour won the last election despite Iraq. It won because a sufficient number of voters felt that the balance of the Government's record was positive, or at least better than the alternative. And while neither the original decision nor the continuing war will bring Mr Blair down by themselves, they sap the political strength he could use to fight off his critics on other issues. It is a wound that will not heal.

The divide in Downing Street, in contrast, is a wound he must heal, for the sake of the effectiveness of his government and the party. Mr Brown, for his part, has a clear choice. If he really believes that Mr Blair is damaging the Labour Party and the Government, he should organise an open leadership challenge. If not, he should stop stoking the fires of discontent and tell his acolytes to cool their attempts to destabilise the Prime Minister.

There are important issues at stake in this power struggle: reform of pensions, health and education crowd the Government's agenda. Talk of revolt may be an exaggeration, but there can be no doubt that this is a dangerous moment for New Labour. The prospect of endless sniping and internal paralysis threatens the future of this Government and the well-being of the party. If the new flare-up following the party's local election losses shows anything, it is that one way or another the enervating Blair-Brown dispute must be resolved one way or the other.