Blair is a touchy-feely leader. But the feeling now is he has lost his touch

When he was a young and rising politician, Tony Blair used to charm the piranhas of the press by confiding in them that he sometimes thought he was about to be "found out". It was a self-deprecating double bluff, because the one thing he has never lacked is confidence. But he would not be human if there were no tiny part of his mind that harboured the fear that it might all suddenly be taken from him.

And is he now being found out? Everything ought to be going his way. Exonerated by Lord Hutton, he finds he has even been obeyed in his instruction to the nation not to mention the war. At last the caravan of journalists and politicians has moved on. And a fat lot of good it has done him over the past week.

The imminent release of five British citizens from Guantanamo Bay is a no-win game for him. The Sun wants them locked up as soon as their feet touch British soil - after all, the President of the United States has said: "The only thing I know for certain is that these are bad people." The Daily Mail, meanwhile, describes the continuing detention of the remaining four Britons as a travesty of justice. Which way is a man once derided as a "tabloid politician" to turn?

This left-over from the war before last is just as far from resolution as it was 17 weeks ago when Blair told his monthly news conference: "I think we are going to bring this to closure one way or another within the next two weeks."

Prime Ministerial optimism is now a seriously debased coinage. It has been ever since the great devaluation of March last year, when Blair's absolute blue-eyed conviction that there would be a second resolution on Iraq at the UN turned out to be a mere ordinary mortal's wishful thinking - oops, there we go again, mentioning the war.

More serious for Blair, however, is the evidence that his judgement is shot. The big setback for him last week was the confusion over policy towards arrivals from the new European Union countries after 1 May. As the Conservative leader, Michael Howard, helpfully pointed out, it is not as if the enlargement of the EU should come as a surprise.

It therefore did come as a surprise this month when Blair failed to respond to a question from Howard in the Commons by saying: "We had all these scare stories at the time Portugal and Greece joined and nothing happened." Instead, he said: "There is a risk that people from the accession countries will come into the country."

The surprise, sadly, is not that the Prime Minister accepts xenophobic press coverage as the basis for government policy, but that he should have failed to see this outbreak of xenophobia coming. Blair's claim to the leadership of the Labour Party ahead of Gordon Brown was that he was the better judge of public opinion - and for the past 10 years his instinct has usually been right, often in both senses of the word.

It is even more unusual for Blair to fail to respond to such an outbreak of press hype within the same 24-hour news cycle. Yet this month he went through two successive Prime Minister's Questions without a policy, while the Home Secretary was widely reported as saying that what Downing Street wanted could not be done.

It was only on Monday that Cabinet ministers' heads were banged together and measures agreed but, because the Government is on its best behaviour, refusing to brief journalists before MPs, we will not know the detail before David Blunkett's statement to Parliament tomorrow.

Most personally embarrassing for Blair was the calculated snub at the Berlin summit on Wednesday from the French president, Jacques Chirac. Harold Macmillan had a point when he said that you should never hold a summit unless the communiqué has been agreed in advance. That was perhaps taking his pose as a cynic too far. Sometimes summits are needed to resolve pressing problems, but it is a basic rule of diplomacy, if not life, that a meeting should have a clear and agreed purpose.

The Berlin summit broke that rule. Its only purpose, from Blair's point of view, was to advertise his inclusion in the ruling clique. It was playground politics and the unpopular kid walked into the bullies' trap. Any child knows that if the two boss kids invite you to join their club, you look out for the catch.

It seems Blair was so desperate to be "in" that he did not think of that. Nor did he pause to consider the offence caused to his hard-won allies in Italy, Spain and the "new" Europe who supported him over the unmentionable war. He then enjoyed the worst of both worlds by being publicly humiliated when Chirac said the troika of Blair, Chancellor Schröder and him could not be compared with the "intense" relationship between Germany and France, "illustrated by our regular, almost daily contact".

It was one of those rare moments, as when Blair was slow-handclapped by the Women's Institute, or unexpectedly lectured by President Assad of Syria on the difference between terrorists and freedom fighters, when he visibly wished he were somewhere else.

But why did he, normally a natural diplomat and a fine judge of the egos of world leaders, make such a clumsy error? It makes no sense to blame poor Foreign Office preparation: this was a prime ministerial blunder.

And it is beginning to look like a systemic failure. One obvious contributory cause is the departure of Alastair Campbell last autumn: for six years in government after three in opposition, he kept a strong grip on the Blair message. Campbell has been much maligned, not least for his loss of perspective over the BBC reporting of David Kelly's doubts, but his muscular news sense was a perfect match for Blair's feel for public opinion.

Campbell is irreplaceable: the only other person who can give Blair that kind of day-by-day, or hour-by-hour, advice is Peter Mandelson. The co-creator of New Labour and former Cabinet minister may be back in Downing Street, but his relationship with the Prime Minister, as Chirac might say, is not as "intense" either as Campbell's was or as his own used to be.

This weakness, if it continues, could be cumulatively terminal for a politician whose record has recently been unfairly belittled by a short-sighted conspiracy of the Labour left, Conservative right and anti-war middle - who ought to hate each other more than they do him.

Blair's claim to power has always rested on competence rather than ideology. If he has lost his touch, he needs to get it back, quickly.

John Rentoul takes over this week as the chief political commentator of 'The Independent on Sunday'