Tony and Gordon: a troubled double act that needs to change its script

The story of Tony Blair, Gordon Brown and the euro is one of dizzying twists and turns. Sometimes the two of them are deadly serious, behaving like two men with the weight of the world on their shoulders. The Prime Minister has described his "historic objective" of joining the euro. Meanwhile, the Chancellor is about to publish thousands of words assessing the economic impact of the single currency – and words do not come more serious than that.

On other occasions the double act plays the euro for laughs. Brown's press secretary gave a comic turn in the Red Lion pub in 1997, briefing Blair and journalists down a mobile phone that the euro was being kicked into the long grass. When the mood takes him, the Prime Minister can be mischievous, too, telling The Sun that he "loves the pound" while winking to pro-Europeans that he plans to get rid of it. Quite often they reverse roles. One can be serious, while the other gets the laughs: taking it in turns to be Ernie Wise, then Eric Morecambe. Sometimes one of them can be sceptical of the euro, while the other is more in favour, the hero of The Sun and then the villain. For years they have mesmerised their audience with their interchangeable unpredictability.

Now, ladies and gentlemen, the double act is falling apart. They have lost control of the convoluted script. They are bewildering each other, as well as the rest of us. This is no longer a laughing matter. Shortly, the double act will announce whether the euro has met their economic tests: their verdict will be "not yet". The two of them can agree on that – but on virtually nothing else. Blair wants to keep the option of joining the euro open for the rest of this Parliament. Brown does not. Blair seeks a statement that ranges beyond the economic tests. Brown does not. They cannot even agree when the statement will be made, although it will not, after all, be this week as originally planned.

As ever, in this story of the double act and the euro, nothing is quite what it seems. Some of the Prime Minister's closest supporters portray him as the great visionary battling against the scheming euro-sceptic Chancellor. In these people's version of events, Brown is cast in the President Chirac role, the obstacle in the way of a bold and principled prime minister. They do not seem to have noticed that Blair has said "no" to the euro for the second time, first in October 1997 and again now. They are battling to keep the ball in the air. He is fighting on their behalf, but here is the harsh reality: halfway through this Parliament, with the Prime Minister a "war hero", he will not risk a referendum. Will he regard such a move as less of a risk in a year's time when the general election is also moving into view?

Those pro-euro supporters less entranced with the notion of Blair as a bold visionary have their doubts about whether he will be quite as keen when the time comes. I keep on bumping into people who have received personal assurances from him that he will hold a referendum next year. They are seeking a statement that gives him no choice but to stick to his word, a detailed route map to the euro in this Parliament.

Contrary to the latest caricature, Brown is not a euro-sceptic and believes that it is in Britain's interests to join the single currency fairly soon, almost certainly early in the next Parliament. He is genuinely worked up about the economic implications of joining at the wrong time, and has spent much of his waking hours recently reading documents on why Britain mistimed its entry to the gold standard and the Exchange Rate Mechanism. It should be noted, though, that his caution over the economic tests conveniently matches his political assessment that a referendum is unwinnable in this Parliament and a distraction from the focus on public services.

Both positions in the double act are flawed. Brown speaks of the economic tests as if he were Alan Hansen commenting on a football match. He is the Chancellor, not a pundit observing passively the progress of the tests. If it is in Britain's interests to join the euro, it should be an explicit aim of his economic policies to make sure that his tests are met. Blair speaks privately of his determination to hold a referendum next year, but his cause was not helped by the war against Iraq when the other part of the double act contrived to portray himself as the bold leader taking on the weak, vacillating French and Germans.

This is all potentially disastrous. Pro-euro supporters suggest the tensions between Blair and Brown are worse than ever – which is saying something. Some of them want the Prime Minister to play the nuclear card and threaten to sack the Chancellor. Here they inadvertently highlight another twist in the story: Blair is in no position to sack Brown; he cannot win a referendum without the support of the Chancellor. Imagine a referendum campaign with the former Chancellor leading the "no" vote.

Here is another twist. Although I do not underestimate the current sweaty tensions between the two of them, the differences are not as great as they seem. Blair wants to keep open the option of a referendum next year, but he might not take it when the time comes. Brown wants that option ruled out, but there were signs in the last Budget that he was starting to prepare the ground for entry fairly soon. Blair and Brown are not separated by an unbridgeable chasm.

There is, though, a danger that each part of the double act will use the other as an excuse for his own dithering. Blair was "bold" when he had President Bush and Rupert Murdoch on his side over the war against Iraq. Now he can blame Brown if he fails to act boldly over the euro. The Chancellor can blame the Prime Minister for attempting to drag him prematurely into supporting the euro, thereby destroying what he regards as his more carefully paced strategy for entry.

What twists and turns there have been. But the biggest twist of all is this: the polls suggest that the euro is as unpopular as ever. After six draining years in power the double act has failed to make the case. Trying to be too clever by half, they have not got anywhere at all.

They need a new script based on this premise: the referendum campaign should begin unofficially the moment they have delivered their "not yet" verdict. They will hold the referendum when polls suggest conclusively that it is winnable, which may be next year – as Blair wishes – or after the next election – as Brown would prefer. Thank you and good night.