Alan Watkins: It's a pity about poor Mr Brown. I'll wager he'll win the crown, but lose the kingdom

This week Mr Gordon Brown will address the conference to loud and prolonged applause. He is not a polished performer, though he has had a lot of practice by now. He tends to get the timing wrong, and he gabbles his words. But the comrades are prepared to accept him as one of themselves. At the TUC gala dinner a couple of weeks ago, he gave the Labour movement credit for, among other achievements, abolishing the slave trade. In fact this was brought about by Evangelical Tories.

No doubt Mr Brown could add to the list the circulation of the blood, vaccination, anaesthetics and sliced bread. After all, in his speech at Bournemouth seven years ago - is it really as long ago as all that? - Mr Tony Blair claimed the ancestry of William Beveridge and David Lloyd George, liberals both, not to mention J M Keynes. And where Mr Blair leads, Mr Brown cannot be far behind in the credit-claiming stakes.

For the past few weeks, we have been obsessed with the precise date of Mr Blair's departure. Or, rather, others have been obsessed by it, for I have been contemplating a more distant prospect. When Mr Blair leaves, some time in 2007, Mr Brown will succeed him, even if it is after a contested election.

In the People's Party, if it can any longer be called that, the favourite usually wins. Even the election of Michael Foot in 1980 was more an apparent than a real exception. The Tories have always, by contrast, done the unexpected: Alec Douglas-Home, Edward Heath, Margaret Thatcher, John Major, the whole lot of them culminating in David Cameron.

My forecast, as I survey the distant scene (and as the hymn "Lead Kindly Light'' advises us not to do), is that Mr Brown will succeed Mr Blair as Prime Minister and that Mr Cameron will win the next election. At least, the Conservatives will win the most seats.

Mr Brown will have served for under three years, so bringing him into the category of Henry Campbell-Bannerman, Bonar Law, Neville Chamberlain, Anthony Eden and Douglas-Home. Only one of these, Campbell-Bannerman, had a good record. The others who served for slightly longer, Arthur Balfour, Heath and James Callaghan, did not perform any too brilliantly either. There is a premium on prime ministerial longevity, with the exception being provided by Sir John Major.

It is a pity about Mr Brown. But by 2009 or 2010 (and I can see Mr Brown trying to serve out a full Parliament, as Douglas-Home did in 1964 and Sir John did in 1997), nevertheless the voters will have had enough of Labour. Of course I may be wrong, we may all be wrong, but that is the long-term forecast.

Note that I am not predicting an absolute majority for the Conservatives. Even so, I would be prepared to invest a small sum in the Tories to win outright. This would amount to around 320 seats. Allowing for the Speaker and his or her auxiliaries, together with a couple of non-voting Irishmen, we come up with a figure of slightly under half the total number of members.

Among the Liberal Democrats at Brighton last week, it was a subject which dared not speak its name. Nor was this surprising. Sir Menzies Campbell (or "Sir Ming'', as all the papers have taken to calling him) has prudently followed Charles Kennedy's policy of refusing to speculate about what would happen if neither of the big parties held an overall majority.

For one thing, the Lib Dems absurdly claim that they are going to achieve power on their own, which is what all political parties pretend to believe. For another thing - a more cogent reason - persistent questioning from the press can tie up the most clear-headed leader in sticky tape.

As Sir Menzies explained in his question-and-answer session with Mr Michael White of The Guardian last week, previous leaders had been by no means clear about these matters. Indeed, at the 1987 election, David Owen and David Steel kept contradicting each other, Lord Owen inclining to the Tories, Lord Steel to Labour. Sir Menzies did not want to go through all that again, even if he was on his own this time.

The truth is that there is no great mystery about what happens in the event of a hung parliament (a phrase which, deriving from the USA's hung jury, came from the early 1970s). The largest single party forms a government, until it is prevented from carrying on by a vote or votes in the House.

In 1924, however, Labour was behind the Conservatives in Parliament but formed an administration with Liberal support until it was brought down later in the same year. In 1929, Labour was the largest party but was only just ahead of the Conservatives. It all ended with the 1931 financial crisis and the subsequent election.

In February 1974, the wretched Heath tried to adhere to office even though he had four seats fewer than Labour. But even with the 14 Liberals, he would not have achieved an absolute majority in the House. There is some dispute about what precisely was on offer from Heath to Jeremy Thorpe (who is still in the land of the living). In any event, Mr Thorpe was quickly sent packing by his own party.

In October 1974, Harold Wilson won by a tiny majority and was disappointed that he did not win by more, though he was by then thoroughly sick of the whole business, as he was to demonstrate by resigning in 1976. In the same year Callaghan, by now Prime Minister, lost his majority as the result of a by-election. The result or, at any rate, a result was the Lib-Lab pact of 1977-78.

I do not think the Liberals got much out of this arrangement apart from receiving regular handfuls of cheery abuse from Denis Healey. Certainly Lord Steel failed to obtain proportional representation for the European elections. What the Callaghan Government did was to make European treaties subject to ratification by the Commons rather than solely by the Crown. This was not a sop to the Liberals but, rather, to the Labour backbenchers who were predominantly suspicious of European elections of any description whatever.

The consequence was the Maastricht rebellion which, in one Commons vote, defeated the Major Government, though that was put right next day by means of a vote of confidence. Everyone has now forgotten, and few noticed it even at the time, that Sir John lost his majority too. He still managed to see out the full term, though much good did that do him in the end.

It is beyond the powers even of Ms Clare Short to campaign specifically for a hung parliament. The numbers of Liberal Democrats have risen steadily while the Labour numbers have fallen only slightly, and Labour is still in power. It is a matter of arithmetic chance. The Liberal Democrats could still hold the balance even if they ended up with fewer seats than they hold now. Somehow, I think they will do better than that.