John Rentoul: Roy Jenkins was a puffed-up gasbag, and it's lucky Mr Blair ignored him

The Eurosceptics' fox has not just been shot, it has been hanged, drawn, quartered and the bits laid out for public view. At last, Tony Blair has achieved something to which he has long aspired, namely a decisive victory over the forces of anti-Europeanism in this country. And he didn't even have to lift a finger. The voters of France and the Netherlands have killed off the European constitution for him. All he has to do is look solemn in public for a while, suppressing his private glee at the paying off of his gamble last spring when he promised a British referendum. That killed Europe as an issue in the election, and now the constitution itself is dead.

The Eurosceptics' fox has not just been shot, it has been hanged, drawn, quartered and the bits laid out for public view. At last, Tony Blair has achieved something to which he has long aspired, namely a decisive victory over the forces of anti-Europeanism in this country. And he didn't even have to lift a finger. The voters of France and the Netherlands have killed off the European constitution for him. All he has to do is look solemn in public for a while, suppressing his private glee at the paying off of his gamble last spring when he promised a British referendum. That killed Europe as an issue in the election, and now the constitution itself is dead.

So what can the swivel-eyed, anti-metric, straight-banana Little Englanders whinge on about now? The euro? One of Blair's surprisingly little-noticed shifts in the election campaign was to say that it was "not very likely" that he would seek to adopt the euro before he left office. The 48-hour working week? Last Thursday the renewed attempt to standardise working hours was blocked by Britain with the support of Germany, Italy and Poland. It is not as dead as the European constitution, but it is plainly never going to get out of its coffin. The Common Agricultural Policy? It is being reformed, albeit too slowly, but if British sceptics want to lend a shoulder to the Prime Minister's attempts to speed up change, he would happily accept their support.

That is it, then. The poison that has infected British politics for so long has been drained. The issue that brought down Margaret Thatcher and John Major is not going to catch Tony Blair out after all.

That has consequences for the Opposition as well as the Government. It has been suggested that the death of the constitution renders the Conservative leadership safe for Kenneth Clarke. Sadly for admirers of the man who laid the foundations of Gordon Brown's economic success, among whom are numbered many former Conservative voters, some even who could be described as normal, the bookies still have him at 10-1. It would seem that David Davis, who has been described as the only man who can swagger sitting down, is increasingly assured of victory, regardless of the electoral system his party chooses. But he, too, could benefit from the sudden collapse of British anti-Europeanism. Despite the fact that most voters agree with the Eurosceptics' suspicion of Brussels, the obsessive quality of their rhetoric has had an alienating effect. The collapse of the constitution makes it possible for a clever Tory leader such as Davis to adopt a more constructive approach to the EU that might begin to heal the party's historic rift over the issue.

However, the main effect of the collapse is to provide space for Tony Blair to secure his legacy, as even Mr Watkins, no friend of the Prime Minister, observes on the opposite page. Blair's triumph over the forces of Euroscepticism may well be bittersweet. This was not how it was meant to be. He wanted to hold a referendum on adopting the euro "early" in the last parliament - but it was never politically possible, or, rather, it was never economically desirable enough to make it politically possible. This victory seems empty by comparison, but we should not underestimate the extent to which enlargement of the EU last year, followed by the implosion of the Franco-German dream of a constitution, creates the chance for Britain to assume a leading role at the heart of Europe. And, as luck would have it, Blair assumes the presidency of the EU next month, so that he can shape the Schadenfreude felt across the Continent at Jacques Chirac's unforced error.

Not having to fight a referendum in this country also gives Blair the time to work on the rest of his legacy. There is enough to do: a plan for Africa; the attempt to engage the US with the problem of climate change; and public service reform at home. Progress on Africa and climate change will take longest, but Blair's window of maximum influence closes at the end of this year, with the end of Britain's simultaneous presidency of the EU and of the G8. Progress on public service reform, on the other hand, partly depends simply on Blair's longevity in office. The longer he stays in No 10, the more the gains of market-style reform, particularly in the health service, will come through. With no referendum next year, his chances of surviving for longer have increased.

It is often said that Blair's achievements in office have followed the law of diminishing returns since the striking breakthrough of the Good Friday Agreement less than a year after he became Prime Minister. I am not so sure. It is true that the Iraq war divided Europe and made it impossible for Blair to win wider support for his ambitious idea of a liberal interventionist world order. Yet despite the divisions over Iraq, and despite his failure to adopt the euro, Blair has aligned himself with European public opinion. He is tactfully waiting for others to sign the constitution's death certificate. But it is obvious that what the peoples of France, the Netherlands, Britain and all other member states are interested in is how the benefits to them of the single market can be maximised. Which has been the focus of British European policy, all along.

I do not want to show disrespect to the great man, but I always thought Roy Jenkins was a puffed-up, pompous gasbag and that it was one of Blair's worst mistakes to give him the time of day. On the other hand, it was a testament to the quality of Blair's judgement that he ignored every piece of Jenkins's advice. As well as wanting him to put Liberal Democrats in the Cabinet and complicate the voting system, Jenkins urged him to take the heroic, courageous course of fighting and losing a referendum on the euro in his first term. As if that would have decisively confounded the sceptics and converted the British people to the virtues of the patrician model of the top-down Europe - the model that was defeated by the French and Dutch referendums last week.

Blair's chance to lead Europe from its new centre of gravity in the direction of a liberal, flexible and more democratic market means that it will be harder for the Eurosceptic press and politicians to present the EU as a conspiracy to subsume Britain in a superstate. That fox is dead. It did not require courage from Blair, except in taking a calculated risk on the promise of a referendum he now will not have to hold. Nor did it require him to go into confrontational battle with other member states. All it took was patience, and now he has achieved the ambition that eluded at least three of his predecessors - Harold Macmillan (to whom de Gaulle said Non), Ted Heath and John Major - of putting Britain securely at the heart of Europe.