Modern healthcare and medical technology have helped transform the health of the nation in the last 50 years.

Life expectancy has increased by just over seven years for men and by more than eight years for women. Children were five times as likely to die in infancy in 1948 than today.

And many killer diseases like TB and influenza have either been defeated or at least brought under control.

Much of this success is less down to the creation of the National Health Service (NHS) and more to an accident of timing.

The development of the NHS coincided with the widespread introduction of new drugs like penicillin, which transformed the way infectious diseases could be fought. The development of vaccines against polio, measles and other diseases dramatically improved our health.

Few can comprehend the advances made in healthcare over the last five decades.

"It's difficult for people now to imagine a world without antibiotics, in which people died of infection all the time," says Dr Leslie Temple who qualified in the 30s.

In the decade before the polio vaccine was introduced there were 45,000 cases. Since 1985 there have been fewer than 40.

Dr John Marks remembers his first day in the NHS.

John Marks qualified as a doctor on day the NHS itself came into operation, and clearly remembers the scene:

"We had wards and wards full of people with tuberculosis, crippled with rheumatic fever, people dying of streptococcal infections. We had an enormous unmet need," he recalls.

Antibiotics have been so successful, it has completely changed the way illness is managed. We now spend much less time in hospital. The average stay these days is just seven days, down from 45 days in 1951.

The NHS was born out of a society in the grip of post-war austerity and poverty with appalling housing and social conditions. As the wealth of the nation recovered - we are now three times richer - so the health of Britons also improved.

Dr Geoffery Rivett, former health civil servant, charts the development of healthcare.

But could we do more to improve our health?

Crucially, fewer people are smoking - nearly half of all adults smoked in 1974 and that figure has been reduced to about 1 in 4. But worryingly, more youngsters are taking up the habit.

We are less physically active than previous generations - surveys suggest that six out of ten men and seven out of ten women do not do enough exercise.

Children no longer walk to school and their parents are less likely than ever to have a job involving manual labour. And too many people eat too much of the wrong type of foods. Despite a dazzling array of fresh produce, we are still not eating enough fresh fruit and vegetables which can have a major impact in reducing mortality from heart disease and cancer.

It is hardly surprising then that we are getting fatter.

Dr Susan Jebb, head of obesity research at the Medical Research Council's Dunn Clinical Nutrition Centre, says: " Obesity is the greatest public health problem in the UK today and the rate of increase in the prevalence among all age groups is alarming."

About 15% of men and 16% of women are classified as obese, and one analysis has calculated that the cost to the NHS of treating the health-related problems is in excess of £1m a week.

So we are not doing enough to help ourselves. But we all expect the NHS to be there to pick up the pieces when something goes wrong. Perhaps the NHS should be re-christened the National Ill-Health Service.

Health experts recognise that more emphasis must be placed on preventative medicine and encouraging all of us to take our health in our own hands.

To this end, the government has published a strategy for improving the general health of the population. It has four broad targets - covering heart disease and strokes, cancers, accidents and mental health - which, If they are met, should prevent 15,000 premature deaths a year.

With our help, the NHS can do better.