Steve Richards: I have changed my mind: Blair must go this autumn to avoid further humiliation

The alternative is a painful, lonely, drawn-out exit, more excruciating than John Major's final days

There is an unwritten rule in British politics. Governments do not become accident-prone by accident. A series of relatively trivial mishaps acquire importance only when they are part of a wider and more significant pattern.

In a column on Tuesday, I argued that John Prescott should stand down as Deputy Prime Minister. He was causing Labour unnecessary grief at a time of other immense difficulties. Several Labour MPs had phoned to tell me that they were getting more complaints from constituents, especially women, about Mr Prescott than any other issue. There was a need, I felt, for Mr Prescott to make a sacrifice so that the Government could move on.

But I argued also that Mr Prescott should stay on as deputy leader of his party. Under no circumstances should there be a deputy leadership contest until Mr Blair goes, presumably at some point next year. Such a contest had to be part of a new era, and not seen through the bleakly distorting prism of Mr Blair's final phase in power.

After writing the column, I reflected on my proposed contortion. Mr Prescott should give up power, but remain deputy leader so there is no contest until Mr Blair leaves. The contortion was necessary because I worked unquestioningly on the assumption that Mr Blair would, and should, remain in place until next year.

So much is being contorted on this basis. So many mishaps, from botched cabinet reshuffles to Mr Prescott's awkward position, are connected in some way or another with Mr Blair's apparent resolve to stay on at least until next year.

Then I got a call from an ultra-Blairite MP, so ultra that he has been telling me persistently and powerfully that Mr Blair should continue in office until 2008, at the earliest. He phoned to say he had changed his mind. He had concluded that the time was up for Mr Blair, partly because of the reaction to the prime ministerial speech delivered in Washington last week.

On the whole, the MP thought the speech was excellent, but he despaired of the way it had been reported in the US and in Britain. The context had overwhelmed the substance. The speech was interpreted largely as the words of a leader at the end of his period in power and, furthermore, a leader struggling still with the consequences of the war against Iraq. The message was lost.

He told me also that political colleagues in Europe were no longer interested in Mr Blair. Already their attention was focused on the succession. Here is another wild contortion. Across the world everyone is moving on, but Mr Blair stays put.

Until recently, I have been against a departure for Mr Blair this year on the grounds that he had declared he would serve a full term. It would look as if the Labour Party had by-passed the wishes of the electorate. I still believe it would be disastrous for Mr Blair to be perceived to have been forced out, but his unusual pre-election pact with the electorate merits an urgent re-examination.

Mr Blair uttered his famous words about serving a third term, but not a fourth, at a moment of weakness. In doing so, he managed to transform the situation, acquiring fleetingly a position of renewed strength. He made the statement in 2004, after another stormy party conference. Yet again, Iraq was the cause for the storms. In addition, news was about to emerge that he had bought a house, signalling the possibility of political retirement. He was also about to go to hospital for an operation. In such a fragile context, he announced he would not fight a fourth election.

Nearly all the attention since has been on that part of his statement. There is a misjudged consensus that he made a terrible error in setting a time limit to his power. But he was attempting to do something much bolder. At a moment of vulnerability, he sought to acquire the political space to remain in office for several more years, possibly exceeding the length of Mrs Thatcher's tenure.

Mr Blair's declaration did indeed buy him some space. Rumours about a possible change of leadership ceased immediately. We should not forget that in the early summer of 2004, Mr Brown was working on the assumption, based on private conversations with Mr Blair, that he would be taking over the crown more or less at the time when Mr Blair declared his intention to serve another full term.

But the time that Mr Blair gained with his declaration has been at least as torrid as the months that preceded it. After Mr Blair's statement, his close allies predicted a third election victory would restore the prime ministerial authority undermined by Iraq. This has not happened, partly because the victory was dependent on a last-minute decision to give Mr Brown a high profile, but more fundamentally because Iraq continues to be a nightmare.

Unlike Mr Blair, I doubt if history will judge the war against Iraq in a kinder light than the contemporary verdicts. I suspect, though, history will be a lot kinder in relation to the dilemmas he faced in advance of the war. In a way that is underestimated by those who loathe him, he faced some nightmarish choices in deciding how to act, as any Labour prime minister would have done.

That is for another day. What is obvious now is that Labour faces a more daunting challenge than at any time since it lost the election in 1992. As the former minister, Denis MacShane, argues in this week's Tribune, support for the Liberal Democrats has been falling for some time. He points out that they have lost a thousand council seats since their post-1997 peak. Such is the electoral geography, a collapse in support for the Lib Dems at the next election is much more likely to benefit the Conservatives.

Mr MacShane's assessment confirms the detailed feedback I am getting from Labour councillors defeated at the recent local elections. From around the country they sense not so much a Conservative breakthrough, but more that the anti-Conservative coalition is breaking up.

None of this is fatal for the Labour government, but there is an obvious need for a change of leadership to clear the air. Already I dread the alternative and more likely set of events. Mr Blair stays on. Another Labour Party conference takes place in which every word and deed is interpreted for signs of Mr Blair's intentions. A Blairite Queen's Speech will follow that will be seen solely in terms of his personal authority. More dire election results will follow next spring. There will be too many accidents.

Mr Blair should take a dignified bow at the party conference in the autumn. The alternative is a painful, lonely, drawn-out exit, more excruciating I fear than Mr Major's final days, humiliating for Mr Blair and disastrous for his party.

s.richards@independent.co.uk