Alan Watkins: Unless Yates of the Yard is the Grand Old Duke of York, then Mr Blair will have to go

Listening to Mr Tony Blair on Friday morning, I was struck by his self-confidence, or his apparent self-confidence. Both these characteristics are usually in generous supply. He had one or two matters to clear up first, after which he would be at Sir Cliff Richard's disposal. That was rather the impression which was given.

Not only would he take his leave as he had planned, even if he had been forced to modify his plans drastically at the last party conference, following the peasants' revolt. More than this: Mr Gordon Brown, the beneficiary of the September rebellion, could not be guaranteed an unimpeded run to the finishing line, even if he had become established since autumn 2006 as the agreed successor to Mr Blair.

The Prime Minister was not proposing somebody else as a suitable opponent for Mr Brown or, at any rate, I do not think he was. He was saying it would not be democratic for Mr Brown simply to succeed him as Prime Minister, without a contest of any kind.

And quite right too. For once, I agree with Mr Blair. I have been saying the same for months, years even. But such has been the pressure building up behind Mr Brown that countervailing forces to the Chancellor have become of little account.

It is odd, in a way, to find Mr Blair commending the ancient traditions of the People's Party, when he has spent the best part of his time denying them. But there it is. Every single leader since Ramsay MacDonald has been elected. The exceptions were Arthur Henderson and George Lansbury. C R Attlee was then elected in 1935.

It was the succession as Prime Minister rather than as leader of the Labour Party which Mr Blair mentioned in his interview with Mr John Humphrys. In the case of Labour, and, since the Tory reforms of the 1960s, of the Conservatives also, it is a distinction without a difference.

In 1957, after the enforced resignation of Anthony Eden and the thoroughly undemocratic elevation of Harold Macmillan the Shadow Cabinet, not the National Executive Committee, laid down that the new Prime Minister would be elected by his parliamentary colleagues. James Callaghan was elected in 1976 and John Major in 1990.

The Labour franchise was extended in 1981, in my opinion foolishly, and was modified in 1993 to give effect to the principle of one member, one vote - though trade union practice in the electoral college varied, as we shall no doubt witness for ourselves in the party elections of 2007. Whether an election for leader is held or not (as Mr Blair clearly hopes it will be), there will undoubtedly be a contest for the deputy's job.

The balance of power in the 1980s shifted from the parliamentary to the party as controlled by the national executive. In the 1990s, the committee became largely a creature of the leadership. In recent months, there have been signs of a change. So have there been in the Cabinet itself.

But who would tell Mr Blair to go? Mr David Cameron could not do it. Indeed, Mr Cameron's observations at Prime Minister's Questions and on subsequent occasions would solidify the support behind Mr Blair, at least for purposes of public consumption. Mr Cameron could write a much more affecting script: "Years of service ... physical strain ... bound to show it ... good luck in the future ... best wishes... ." There would scarcely have been a dry eye in the House before the management had decided to introduce a new act to bring in the audiences once again. Alas! Mr Brown is disqualified, whether as witness or as advocate. He must keep quiet. He has got his promise - September 2007 at the latest - and he will have to make the best of that.

The ostentatiously loyal Ms Hazel Blears and the perhaps less than wholly devoted Ms Harriet Harman said on the BBC last Thursday that the goings-on in Downing Street were not good for morale. But neither of them is likely to say: "Tony'' - or the correct usage may be "Prime Minister'' - "you must go at once.'' If they did, Mr Blair would not be likely to take much notice of them. Mr Jack Straw and Mrs Margaret Beckett might be given more attention.

Mrs Beckett used to be the tricoteuse, or one of them, beside the revolutionary guillotines of the 1980s. She did not actually pull any levers, but she certainly accused Neil Kinnock of treachery when he refused to support Mr Tony Benn as deputy leader. But see what has happened: Mrs Beckett has become respectable. She may have become dull, though she was always on the quiet side. But she is now listened to, goodness knows why.

Mr Straw has more substantial credentials. He likewise was a nuisance in his hot youth. He gave some hints that he was uneasy about certain aspects of Mr Blair's foreign policy, which may be one reason why the Prime Minister shifted him to the leadership of the House. His monument, which casts a ghostly glow over the entire cemetery, is his Political Parties and Referendums Act 2000.

It is a very long statute. It was put together mainly in response to the excesses of the Major years, though these seem inconsequential enough by the standards of a later period. Truly, God is not mocked.

Mr Blair seemed to think that, after a few weeks, the constabulary would have concluded its investigations and normal service would be resumed. The assumption on Mr Blair's part was that the prosecution would be dropped. It would not be accurate to say that no prosecution had been contemplated, for clearly this had been thought about most intensively by assistant commissioner John Yates and no doubt by numerous others. But matters would not be taken any further.

If so, Mr Yates would resemble no one so much as the Grand Old Duke of York, who had ten thousand men, and who marched them up to the top of the hill and marched them down again. It would not seem to justify Mr Yates in arresting Lord Levy not once but twice, questioning the Prime Minister on the same number of occasions, and arresting Ms Ruth Turner at half past six in the morning. She seems to be a person of the utmost respectability and who may or may not be guilty of breaking the law.

If nothing whatever is going to happen as a result of these exertions, it comes perilously close to the offence of wasting police time, with the police doing the wasting. If something does happen, however, Mr Blair will have to go.

Even so, we should remember that Labour is a sentimental old party. Of Prime Ministers, only MacDonald was forced out of office, and that was because he chose voluntarily - and honourably - to join the National government. Attlee served two terms and Callaghan a short term before being defeated at the polls. Harold Wilson resigned mainly because he feared the onset of senility, which duly and sadly came to afflict him. It is only Tories who are forced out.