The NHS was practically moribund when Labour won power in 1997 but the Blair Government delayed for two years before attempting emergency resuscitation. It has since ordered the largest injection of funds in the NHS's history and launched a recovery plan that would make Aneurin Bevan's eyes gleam with envy. But that initial delay could prove fatal. The big question now is: can the NHS deliver before ministerial and public patience runs out?

The first target Labour set in 1997 was to cut waiting lists by 100,000. How modest that seems now, yet it took a huge effort and hundreds of millions of pounds to achieve. The new, far more ambitious, target is that no one should wait more than six months for treatment by March 2005. As there were 228,000 patients who had been waiting more than six months at the end of January, that will require an enormous increase in NHS productivity which has not, so far, been rising fast enough.

The biggest problem facing the health service is not, any longer, money. It is staff and capacity. There are not enough doctors and nurses, and not enough surgeries, clinics and hospitals. The Government has embarked on a major recruitment drive and a huge hospital building programme funded by the private finance initiative. They are starting to deliver but it takes 15 years to train a hospital consultant and time is not on the Government's side.

The project to save the NHS began in earnest with the launch of the NHS Plan in July 2000, a hugely ambitious document which contained radical proposals for modernising heart, cancer and other services.

Tony Blair took personal charge of the plan and endlessly repeated the mantra "no investment without modernisation". He knows that unless the monolithic state provider, which has often seemed to be run for the benefit of its staff, is turned round to put the needs of patients first, the prospect of saving Labour's greatest creation will be doomed.

Expanding the NHS is only half the story. Improving quality is also crucial. On the back of a spate of high-profile medical scandals culminating in the Bristol babies heart surgery disaster, the Government launched the Commission for Health Improvement and a new system of clinical governance to ensure standards of medical care were checked and doctors kept up to scratch. It was the first time, astonishingly, that doctors had been held to account for their clinical decisions.

At the same time as trying to modernise the service, the Government underwent a Damascene conversion last year from one of the most centralising administrations in history to one that championed localism. The proliferation of centrally set targets was halted and hospitals offered the chance to become Foundation trusts, freed from the shackles of Whitehall.

Foundation hospitals have proved hugely unpopular with the Labour left, who fear they will introduce a two-tier service and a competitive culture. But increasing choice is seen by Mr Blair as critical in persuading the electorate that a state-run health service is a viable institution in a 21st century Britain where 24-hour service from banks, supermarkets and garages is regarded as routine.

Ministers have pledged to give all patients choice over where they are treated by 2005. But delivering on the pledge will depend on expanding capacity and that remains Labour's toughest test.

The NHS has to deliver consistently higher standards and improved access or public support for it will wane. But supporters of what is still the fairest and cheapest health system in the western world are drinking in the last chance saloon.