Today is destined to be a crux in NHS history. The national plan heralds the beginning either of the service's restoration or of its demise. Of course, the NHS's 52 years seem littered with such moments of truth, occurring with increasing rapidity and on an ever more ambitious scale: major reorganisations in 1974, 1982, 1991 and 1999; the introduction of general management, of competition, of a primary care-led service; abolition of regional health authorities and the internal market.

The national plan, we are told, will be a blueprint for the next 10 years; the last 10-year programme - set out in The New NHS white paper - is less than three years old.

But this time the service really has reached a point of no return. Three significant factors conspire to make it so. There is a mood among the public - and indeed, among many healthcare professionals, not to mention politicians - that after so many restless attempts to get it right over so long a period, if the NHS cannot solve most of its perennial problems now it will be time to try a different solution for a different century. To put it bluntly, patience is running out.

Second, it now has a level of resources at its disposal undreamed of a year ago, eradicating the old excuses for falling far short of aspirations. Managers will carry a heavy burden of responsibility for spending them to maximum effect. And third, political reputations have been tied to the outcome of the national plan in an explicit and unprecedented way.

It is not merely health secretary Alan Milburn's future at stake. Tony Blair, alone among post-war prime ministers, has sought to be closely identified with the fate of the health service. Their nervousness is reflected in the number of official leaks, airing aspects of the plan ahead of publication to afford a final chance of changing anything that provokes a savage response; hence the flurry of faxes back and forth from Richmond House to Mr Blair at the G8 summit in Okinawa, and the printing presses held excruciatingly on stand-by over the weekend.

In fact, it is not simply Mr Blair's reputation but the very government's survival which may depend on the plan's success. Victory will ensure for Mr Blair and Mr Milburn a place in the pantheon of NHS heroes alongside Aneurin Bevan; defeat will cast Mr Milburn into political oblivion and quite probably Mr Blair too. It would mean the end of the NHS. They have chosen death or glory. Only a brave or foolhardy gambler would risk big money on the result.

Early victories will be important, to reassure the public that the plan is on course and to raise staff morale. It is hard to discern what these might be before a general election next year, although the total absence of anything the media could construe as a winter crisis will be paramount.

Public confidence in the NHS has sunk so noticeably in the last three years that ministers need to create some hullabaloo around the plan. Yet that will raise expectations, maybe in unrealistic ways. For however extravagantly consultative ministers have been, however generous the resources, tempting the incentives and terrifying the sanctions, there lurks what Rudolf Klein (see page 31) calls the NHS's 'organisational recalcitrance to ministerial dictates'. What must be giving Messrs Blair and Milburn butterflies is the fear that, despite their panoply of controls, the supertanker will plough on towards the iceberg, regardless.

Expect crunch-time around 2003-04. Assuming Labour is re-elected, that would be halfway through its second term and marks the last year - so far - in which the NHS is assured of 5.6 per cent growth above inflation. If the national plan has not borne ostentatious fruit by then, the NHS will have become a massive political liability - and no party, even Labour, would be likely to go on defending it.

But ah, success. . . Proof of that would be visibly excellent conditions for patients and staff, positive media coverage, favourable comparisons with Europe. It would bring cross-party support for the NHS ideal and reinvigorated public confidence. And it would sustain Bevan's legacy well into the 21st century.