In The Treasure who's pushing Australia toward its children's rights exam Prevention Action describes how a young Australian doctor, Fiona Stanley, came to the UK in the early 1970s to study social medicine with Professor Jerry Morris at his Social Medicine Unit. The experience changed her life, she said. As a result, she became a pioneer child health service development in her own country and is now regarded as that “national treasure”.

How might such a man – now in his late 90s – have such a profoundly benign influence on a professional life?

When the young Jerry Morris was appointed Director of the Social Medicine Unit, coronary ischemic heart disease rates (CHD) had risen sharply, mostly among middle-aged men. He and others investigated this “epidemic”.

It was already known that men in manual occupations had lower rates of CHD. So what was protecting them? Was it the physical activity involved in their work; if so, how could this hypothesis be tested experimentally? The answer was the "Busman’s" study that showed Morris at his brilliant best.

In the late 1940s London Transport crews were white, working class and English (a necessary degree of homogeneity for research, later changed by wider recruitment). In the case of double-decker buses, drivers sat in their cabs while conductors controlled stops and collected fares from passengers on the upper or lower decks. Conductors spent their entire shift on their feet continually going up and down stairs; the drivers sat all the time.

The first problem to tackle was "selection in". If an eventual difference in coronary experience between drivers and conductors was established might it be due to selection factors that channeled certain types into one or other of these jobs? Perhaps health status or body size were pre-determinant?

Only by studying large numbers could one factor be singled out for investigation, holding others constant or "standardized". Another stroke of good fortune: at that period London had a single publicly-owned transport service and all job applicants were examined by its own full time medical staff. So there were centrally administered medical records for all men.

Accepted applicants were measured for a uniform at a central depot to get a good fit for jacket and trousers; once again records were kept for each crew member. Unfit applicants were not employed and so uniform size gave a general indication of size and build. A series of driver and conductors matched in health and build were identified narrowing any eventual CHD differences.

The next problem was “selection out”. Even minor sickness leading to leaving the job might be an early sign of heart trouble. Diligent training involving the co-operation of London Transport Medical Services and family doctors was essential. And with each man's prior permission an ultimate “outcome” measure was available – from the national register of death certification.

Of course, the reliability of the information on the death certificate, especially “cause of death”, which doctors were routinely required to enter, had first to be established. Heart disease led to premature mortality but a retrospective analysis across the years to middle age was essential. This follow-up showed a statistically significant higher rate of heart disease among drivers than conductors, matched for many other factors.

Once the message that physical activity helped to protect against the risk of heart disease was put into wide circulation and other studies confirmed Morris's work, exercise, jogging and going to the gym started to become popular, especially for those in sedentary jobs.

Women with lower heart disease rates also took to exercise, so that by the 1980s a new personal lifestyle culture had been born. Especially hopeful has been the spread of regular physical activity amongst young adults where early steps may prevent later health problems.

Of course, the busman’s study left much to be learned. For example, not all men in sedentary occupations (the high risk group) developed heart disease; but how much exercise did they take in their leisure time?

Out of several years further work reliable assessment methods were developed to establish among a large group of mostly sedentary civil servants how much physical activity they had in their non-work leisure time. Once again, on follow up it emerged that only those with records of vigorous activity such as sport, hard gardening etc. had lower rates of CHD.

"Transparent honesty and thoroughness"

Turning to secondary prevention what might help men who had already suffered a first attack of CHD to avoid a second? The hypothesis that diet was influential in causing heart disease was untested.

Morris and MRC Unit colleagues, together with hospital clinicians, studied 393 male patients who had recovered from a first heart attack. Half were randomly allocated to a low fat dietary regime where soya bean oil replaced saturated fats. The trial lasted six years, monitoring first relapses, major relapses and all deaths from CHD. Outcome showed no difference in CHD experience between the test diet and controls.

During all this research the MRC Unit moved first to the London Hospital and then to the London School of Hygiene and Tropical Medicine when Morris was appointed Professor Public Health.

At each location he expanded the range of studies that applied epidemiology to many problems, such as excess mortality amongst young men – it was motorcycles; to other aspects of diet especially fiber – those with highest intake of cereal fiber developed less CHD.

The association between rates of heart disease, water quality and the regional difference between soft and hard water public supplies was never explained despite years of work.

There was also an interesting failure in relation to studies of juvenile delinquency and increasing court rates: it emerged that rates for 20 similar Tower Hamlets schools varied widely but not because of their catchment areas. It suggested a preventive potential, but the education authority refused further exploratory work.

For all these studies Morris gathered a team of medics, statisticians, dietitians, pathologists, social scientists, and, before computerization, a small army of reliable data processors. All planned work was discussed and debated first by the entire Unit.

No research results were explained to any outside bodies before they had been rehearsed in front of the whole team. Publications went through many drafts, but no interference in the content by outside bodies was allowed.

The transparent honesty and thoroughness of Jerry Morris’s approach doubtless inspired Fiona Stanley.