Britain is poised to blow a golden opportunity to boost its influence in the European Union when Tony Blair's government announces today it is not yet ready to put joining the euro to a referendum.
Not that London's political standing in the 15-nation bloc or among the 10 countries preparing to join next year will be greatly diminished by the widely anticipated decision.
Britain is respected, even by its continental critics, for its energetic foreign policy, its military prowess, financial expertise and strong relationship with the United States.
"In foreign policy, you will remain one of the big two in Europe with or without the euro. But you could be so much more," a Greek EU presidency official told a British colleague.
To many policymakers in Europe, Britain is doomed to remain politically and economically semi-detached. Indeed some Brussels officials fear it may be reverting to a more eurosceptical stance after six years of rapprochement under Mr Blair.
"The sad thing is that this is such a tremendous missed opportunity," says a senior French official critical in private of Paris's active opposition to the US-British war in Iraq.
"Just imagine if Blair, after winning the war in Iraq, had used his Baghdad bonus to lead Britain into the euro. His leadership in Europe would have been unassailable. He would have had the double halo of the model Atlanticist and the man who reconciled the British with their European destiny," he said.
Instead, officials on the European mainland are resigned to pressing ahead with the EU's most important economic project without the bloc's third largest economy.
Although the decision will be couched in terms of economic tests, EU diplomats are sure the British decision is political.
"There is no insurmountable economic obstacle. Blair simply doesn't think he can win a referendum," a senior diplomat said.
Yet it is on economic policy, where it preaches flexibility and reform to its continental partners, that Britain's influence is most likely to suffer by staying out of the euro.
Under proposals set to be adopted the EU's constitutional Convention this month, the 12 members of the single currency are likely to get formal powers to set and enforce a common economic policy at meetings closed to non-members of the euro.
Ironically, Gordon Brown, the Chancellor of the Exchequer who has fought within Mr Blair's Labour government against euro entry now, may be the biggest loser.
By the time he arrives at meetings of EU finance ministers, the big decisions may already have been taken without him.
"There is no doubt that the countries in the euro zone are going to integrate their economies more in the next few years. That is the logic of a single currency," said the EU ambassador of one of the larger euro zone states.
"Up to now, there was some inclination to wait for Britain before taking further steps. Now we will simply move ahead."
That means that when Britain next considers joining, the bar it will have to jump will be higher than now in terms of economic integration, he argued.
Pessimists in Brussels see a pattern. Conservative John Major became prime minister in 1990 vowing to put Britain "at the heart of Europe" after the bitterly divisive, increasingly anti-European final years of Margaret Thatcher's premiership.
But Mr Major became ever more eurosceptical, culminating in a self-defeating blockade of EU business in 1996 after Europe banned British beef imports over mad cow disease.
Mr Blair too vowed to put Britain at the centre of Europe. He sought a leadership role by reversing previous British policy and launching an initiative with French President Jacques Chirac in St Malo in 1998 to give the EU its own defence capability.