Leading article: A vision for Europe that Britain can share

As the French President and his sizeable entourage left Britain last night, there will have been relief on both sides of the Channel that this state visit passed off as well as it did. The relief on the British side will be that nothing went wrong in terms of protocol – nothing worse, that is, than a temporarily lost Prime Minister before the Windsor Castle banquet and an earpiece that troubled him at the final press conference. On the French side, the relief must be that the President's new wife proved so much of an asset and that the haughty British seemed in such a generally Francophile mood. They might reflect that there is nothing like a severe economic jolt and a falling currency to instill a little unwonted humility.

Well before the political summit had concluded – at, of all places, Arsenal Football Club's Emirates stadium – however, the question on many British lips was whether M. Sarkozy would be able to "deliver". Quite what he is supposed to deliver has not been completely spelt out. In France, the widespread assumption was that the state visit to Britain was intended to relaunch the French President as a serious international statesman. The argument was that his party's poor performance in recent local elections and the very public distraction of his romance could be eclipsed by 30 hours of pomp, circumstance and gravitas in Britain.

France will decide whether this state visit can reset the presidential clock. Over here, doubts relate chiefly to the French President's intention to take France back into the Nato military command, hints that he would like the EU to develop in a more Atlanticist direction, and suggestions that he would take a less protectionist approach to French industry. M. Sarkozy did nothing during his visit to Britain to suggest that he had had second thoughts about any of his early intentions. What he did say, however – larded though his words were with charm and flattery – was that for France to succeed in these endeavours, it needed Britain to become more fully engaged in Europe.

This has, in fact, been a theme of French diplomacy for a decade. For there is a view in France, which goes beyond the Gaullist centre-right, according to which Britain is a large, stable and dynamic country that would lend the European Union more internal credibility and external clout, if only it would stop dithering on the sidelines. The French hark back to the St Malo declaration of 1998 which committed both countries to enhanced defence co-operation within Europe. And they will insinuate, if pressed, that the lack of progress since has not been entirely the fault of the French.

It is not necessary to fall for M. Sarkozy's considerable blandishments to grasp that, in his impassioned address to Parliament, he was pleading with Britain – in the nicest possible way – to be a better European. And if this is what he was saying, then the question is less whether M. Sarkozy can deliver, but whether Mr Brown can deliver, or even wants to. Observing his gruff demeanour at yesterday's press conference, as he listed areas of agreed co-operation – banking standards, nuclear power, Afghanistan – we find it hard to believe that he does. His curt response to a question about the euro seemed especially – and unnecessarily – unpromising.

Mr Brown may feel that, until the EU reform treaty has finally completed its passage through Parliament, it is in his, and his government's, interests to affect a lack of interest in Europe.

If only a fraction of what M. Sarkozy said in Britain is true, however, there is a real opportunity here to be seized. The French President offered a coherent vision of Europe which Britain should have the imagination to support.