Leading article: An enervating rivalry that must be resolved sooner rather than later

What on earth does all this mean? Of these multifarious activities, only the Moscow trip could reasonably be described as integral to Mr Brown's responsibilities as Chancellor. All the rest would appear to be preparation for his eventual promotion to Prime Minister.

Following on his Africa tour last year and his speech on Britishness, Mr Brown is now accelerating the diversification of his portfolio and multiplying his opportunities to introduce himself to the people.

In the meantime, key members of the present Cabinet - Charles Clarke, John Reid, Alistair Darling - stated more or less directly that they saw no alternative to Mr Brown as the heir to 10 Downing Street at whatever time Mr Blair chooses to go. The clear message being conveyed was that - as of now - the leadership is united on the matter of the succession; the transition, when it comes, will be smooth and Mr Brown will face no serious challenger.

Some read the signals as evidence that Mr Blair had now accommodated Mr Brown effectively as co-leader; others saw signs of a new understanding between the two and inferred that the Chancellor had been given a date. Still others discerned growing impatience on Mr Brown's part finally to claim his patrimony.

Yet it scarcely matters whether there is a new understanding, a revival of the old Granita restaurant misunderstanding, or no understanding at all. One way or another there has been a perceptible shift in the Chancellor's status and this is unsettling for a country where authority is customarily vested in one Prime Minister. It also poses questions. Who, for instance, is looking after the nation's finances if the Chancellor of the Exchequer is otherwise engaged? And how long is this uncertainty likely to last? If, as Mr Blair suggests from time to time, he intends to serve his full term, we are contemplating at least three more uneasy years.

This is not a happy situation for anyone: not for the Cabinet, not for Mr Brown and certainly not for the voting public. It is easy to say now that Mr Blair made a rare tactical mistake when he allowed himself to be bounced into declaring that the 2005 election would be his last. It was inevitable that speculation about the hand-over would begin almost as soon as the votes were counted last May. Had he not committed himself to leaving before the next election, he would have retained the freedom to depart at the time he chose. That freedom becomes more circumscribed by the day.

Speculation about the handover and jockeying for position threaten to sap the energy of this government. The Prime Minister must finally clarify his intentions.

Mr Brown has placed on record his readiness to join a contest for the leadership, arguing that the country would prefer this to an arrangement stitched up by a coterie of politicians. He is right - and that contest needs to take place sooner rather than later.