It will be a big election, when it comes. The next general election could decide the character of British politics for the next decade. Since 1945, there have been three Conservative administrations, with an average life of about 12 years; the last of them actually held office for 18 years. The current Labour administration has already held office for 12. If the Conservatives win in 2010, they could well hold office until after 2020. The Labour Party should certainly assume that the next election will decide power in Britain for more than a single Parliament.

Labour will find it hard to win the next election, whoever is their leader and whatever their strategy. The first difficulty is the electoral cycle itself, the swing of the pendulum. It may have lengthened to make two terms seem natural, and three at least possible, but a fourth election victory for one party remains very unusual. That is the challenge to Labour. In the 20th century it only occurred once, when John Major won against the odds in 1992. There does come a time when the voters feel it is time for a change.

This mood was already evident before the financial crisis. Gordon Brown lacked the political skills that Labour had enjoyed under Tony Blair, including the fundamental skill of establishing a warm relationship with the voters. Mr Blair was a very gifted electioneer, able to detach whole sections of support from the Conservative shadow ministers who campaigned against him. Mr Brown does not have these charismatic gifts.

Perhaps the southern English middle-class voters would in any case have returned to their natural Conservative home, but the change from Blair to Brown made it inevitable. The southern English voters need to be won back to Labour, but Mr Brown is not the man who can do it.

The political cycle is a problem for him, just as it was for the outgoing Conservatives in 1997 or, longer ago, in 1964. The public think that ministers are exhausted and prone to make mistakes. They are bored with them. However, the economic cycle is an even greater challenge. Mr Brown foolishly claimed to have abolished the business cycle; it has turned round and bitten him.

If he does remain as Prime Minister, Gordon Brown will need all the time he can get to benefit from any economic recovery that may happen next year. This suggests that he will not have a general election until May 2010.

Yet there is no guarantee that 2010 will be a year of recovery. In an early study of trade cycles, the Italian Vilfredo Pareto drew a distinction between the initial panic that destroys speculators “like a house of cards” and the subsequent “repercussions on the workers”, which he described as “the crisis proper”. We may be coming to the end of the first phase of the recession, of the banking crisis itself, but we have only reached the beginning of the real recession, when the crisis spreads to workers in general and therefore to voters. The green shoots may or may not turn into a real recovery in stock markets, but the big social negatives will remain, in unemployment, in debt, in repossessions, and in bankruptcies.

I would not put too much confidence in the stock market rally. In recessions there have always been rallies in a bear market, but that there have been six rallies already does not reassure one that the present rally is the real thing. From a political point of view, the continued rise in unemployment is particularly damaging. It is a worldwide trend. US unemployment has risen by two million this year, and is expected to have risen by a further 500,000 in April.

A British party leader has an increasingly presidential role. There have been postwar leaders, of both main parties, who lacked the essential presidential talents. That does not mean that they made bad prime ministers; Attlee, indeed, was probably the best Prime Minister Labour has ever had. But it would mean that such a leader would not have been effective in the quasi-presidential contest of a general election. They would not have stood up to the ringcraft of an Obama, a Blair or a Thatcher.

The Labour Party in Parliament has a very strong motive to get a new leader if Gordon Brown cannot do this presidential job. Labour MPs want to hold their seats. No Labour seat with a majority much below 10,000 can now be regarded as safe. Mr Brown would need to make these vulnerable majorities at least a little more solid.

Frank Field, the most formidable of Mr Brown’s critics, had said that the Labour Party will have “one last chance” to replace Mr Brown as leader after the European and local government elections that will be held on June 4.

There are arguments against making a change: there is no complete consensus on an alternative leader, though the choice seems to have narrowed down to Jack Straw or Alan Johnson; it is difficult to get rid of a Labour leader; Gordon Brown is in the best position to claim credit for any economic recovery; and the party might be split — though I believe that Mr Straw and Mr Johnson would probably serve under each other happily enough. Either of them would clear out the Downing Street midden of leaking and smearing.

The strongest argument for changing the leader is the one John Redwood made when he challenged the leadership of John Major: “No change, no chance.” There are at present about 200 Labour members who could lose their seats if the worst of the opinion polls proved correct.

Gordon Brown has to carry the responsibility for the economic crisis, the scandals, the debt and the decline in the apparent competence of his administration. Outside Scotland he has very little popularity. Of the two potential candidates, Jack Straw is a first-class tactical politician who would limit Labour’s losses, while Alan Johnson has a reassuring friendliness that would attract voters. Labour should make a change, but it may not have the will to do it.

Times Recommends

• Tear down this wall! And save the planet
• Double click if you want the bin emptied
• Have you got permission to read this?