This will only make the Prime Minister work harder to accomplish his goals

Intimations of mortality are likely to spur Mr Blair to be if anything more impatient to do what he believes he can still achieve

Tony Blair started to feel somewhat breathless last Friday after working out in the police gym at Chequers as almost his first act on returning from the European summit in Brussels. After a night's sleep, however, he was on good enough form to write one of his long notes for his office on tasks ahead, to converse freely and in relaxed terms with friends on the telephone (without mentioning his symptoms of the previous evening, by all accounts) and that night held a sizeable and successful dinner party at the Prime Ministerial country home. On Sunday morning, the breathlessness returned; he and those around him were sufficiently worried for him to visit the nearest hospital, Stoke Mandeville which referred him to the Hammersmith Hospital which has a distinguished cardiac unit. And the rest is history, page after page of it in every newspaper analysing all the plausible implications, political, medical, constitutional, and several implausible ones as well.

This isn't meant to suggest for a moment that his problem was a non-event. Although tachycardia is a relatively common disorder, it's extremely unpleasant and alarming for the patient. But the level of coverage illustrates the change in media-political culture since an era when prime ministers were able to become ill without the same impact on the national debate. When Clement Attlee was fighting a tiresome, and in the end unsuccessful, struggle, to solve the Cabinet crisis over health charges in 1951, he was doing it lying in a bed in St Mary's Hospital, Paddington, where he was treated for a serious ulcer attack. But it was Bevan's resignation that was the big story - rather than the confinement to hospital of a 68-year old Prime Minister.

When Harold Wilson suffered heart palpitations in Paris in 1975, was treated at the British Embassy and packed off to Chequers for a week to recover, he was said to have had flu; the real cause was kept secret because of the possible impact on the markets. In these days of 24 hour media, celebrity politics, a cover-up of that sort is pretty well unimaginable.

Maybe that's no bad thing. In a modern, open democracy perhaps it's necessary to know just how the head of government is at any given moment. A whole plot strand in the television series West Wing is devoted to the sense of betrayal felt by those around the fictional President Jed Bartlett because of his failure to disclose to them and the American people that he has MS. For better or worse, moreover, New Labour and its leader have contributed to the shock and surprise felt if Tony Blair suffered anything more than a common cold - if only because of the party's own, at times, excessive emphasis on the new young, and in Mr Blair's case, superfit.

But the comprehensiveness of the coverage does risk overestimating the consequences of a health problem - as Daily Express readers must be realising after waking up to the headline question: "Is This The End of Blair?" A suggestive case is that of Harold Macmillan who having suffered a long series of illnesses from childhood - and serious war wounds at the Somme - may have over-reacted to his admittedly serious prostate trouble in 1963 by abruptly resigning as PM - before going on to live, with most of his faculties intact, for another 23 years.

It's a safe bet, to put it mildly, that Mr Blair is not about to make the same mistake, any more than countless others who have suffered from tachycardia at one time or another and continue to hold challenging positions at the top of their field. This isn't to make light of the much discussed pressures of the job. In his absorbing and important new book, Point of Departure, the first written about the Labour Government from the inside, and published yesterday, Robin Cook describes a not untypical Prime Ministerial week: fly to Johannesburg to make a speech, go to Sweden to help in the general election, fly to Spain for Jose Maria Aznar's daughter's wedding, go to US for talks with George Bush, and make the "annual pilgrimage" to Balmoral. And all this of course while considering - and discussing by secure telephone - a host of problems within Government which by their very essence are the most intractable ones, which is why they reach the PM in the first place.

And the pressure has worsened since then. His holiday this summer was overshadowed by the Hutton inquiry. Whatever the rights and wrongs on both sides, the tensions of the relationship with Gordon Brown are certainly stressful at times. And if Mr Blair can devolve more responsibilities to a now experienced Cabinet, as he is said to be trying to do, then that cannot fail to be good for his health as well as for politics. And so on.

What's less clear is whether or not the huge tensions of the last year have really got under his skin, let alone undermined his faith in himself, in the way it is now tempting to assume. Mr Blair told the former Times editor, Peter Stothard, for example, that the moral problem of the deaths caused by the Iraq war "really get to you". But Mr Stothard reported him as also talking of the need to isolate himself with self-imposed barriers from the consequences of what he had decided to do.

Those closest to him say it's often the petty small change of politics rather than the big issues which get him down personally: Cheriegate rather than Iraq. Since lack of sleep is occasionally thought to contribute to the kind of problems Mr Blair suffered at the weekend, it may just be that Leo Blair may be as much of a factor as, say, plotting British entry to the euro.

All this is hopelessly speculative, of course. What seems to be less so, according to some of his allies, is that insofar as Mr Blair sees the weekend as an intimation of mortality, it is likely to spur him not only to carry on but to be if anything more impatient to do what he believes he can still achieve. There has been for some time a case for posing the question of just what this is, beyond highly desirable public service reform, and what has happened to some for the goals of remaking British politics that he seemed to represent in 1997. The prospect of a fresh and hugely welcome breakthrough in Northern Ireland is just one example of how there is more to politics even than making schools and hospitals work better or the trains run on time. As Cook argues at the end of his book, political choice is, or should be, about more than who are the most competent managers.

But if that is a political question today, it was also one last Thursday. Mr Blair surely isn't going to do anything which would jeopardise the future years of hugely enjoyable family life that lie deservedly ahead of him. But equally he isn't going to leave voluntarily before he has completed the only shot he has at changing the country as well as the party. And if time is running out to do just that, it has a lot more to do with the remorseless cycle of politics than a brief health scare from which he shows every sign of enjoying a complete recovery.

d.macintyre@independent.co.uk