Blair hopes his stardust will persuade us

Why does Tony Blair think that he can persuade a historically sceptical British people that they should forfeit the pound, and for the euro?

Why, in particular, when the German economy that should be powering the eurozone is languishing while Britain's is in sound health, when reforms inside the EU are dragging and the map of political Europe is being discoloured by challenges from the far Right?

The answer lies in his deep-seated belief that, whatever the obstacles, he can sprinkle some of his personal stardust and transform hostility into support. He has, after all, managed a comparable feat by turning Labour from an election-losing machine into the natural party of government. No political leader except Lady Thatcher has greater faith in the effect of their endorsement on the public's sensibilities.

Quite why Mr Blair - initially agnostic on the euro - has become such an enthusiast for entry is an intriguing part of his development as Prime Minister. He is determined, desperate even, to leave a monument that will rival the memories of the Thatcher government as a time of profound change for Britain. The reformation of the NHS is intended to provide one pillar of such a monument, but Mr Blair knows public sector changes are lengthy and fraught, and that the public is always likely to feel some dissatisfaction with the result.

He requires something more solid as a legacy, and bringing Britain into the single currency would doubtless achieve that. It would be the biggest change in our circumstances since 1945 - binding Britain closer into Economic and Monetary Union, and into the European system as a whole.

In his Paxman interview, he emphasised the image of a Britain outside the euro being "left outside" the mainstream of the Continent's affairs. This threat will be the core message of the Yes campaign.

But his confident tone belies some unresolved matters. He prefers to stress the Treasury's elastic five economic tests. The real bar to entry is the unofficial sixth test - whether an exchange rate can be arrived at which is acceptable to our European partners without damaging exports or igniting inflation. That is still questionable and the Chancellor will certainly have something to say about whether it can be achieved by next May.

The next priority is to ensure that the balance of opposition to support for euro entry keeps whittling away in the direction of a Yes vote.

The polls currently put the Yes camp at around a third and the Nos at around two-thirds. However, many people are undecided.

The Tory Party, the main political face of euro-resistance, is not in great shape and many prominent eurosceptics are either superannuated politicians or rather wild and obsessive in presenting their case. The Blair strategists place faith in the quality of "their" people against the opponents of entry.

Even so, dragging Britain towards the euro remains the most considerable political challenge of Mr Blair's premiership and the greatest risk he has taken with his personal reputation.