The Edinburgh-based doctor helped develop the first effective treatment for tuberculosis in the 1950s, virtually eradicating the often-deadly disease at that time.

His breakthrough – using a “cocktail” of three different antibiotics – became the worldwide standard and is thought to have saved millions of lives, although the disease has since seen a resurgence, particularly in developing nations.

In his later years, the Dublin-

born physician and his wife, Eileen, campaigned for global controls on tobacco, which they considered a major threat, and for restrictions on alcohol, which they said created “misery and horrors”, not least in Scotland. Sir John became one of the World Health Organisation’s leading experts on tobacco control and travelled the world on behalf of WHO.

Educated in England, he was 40 when he came north in 1952 to take up a post as professor of respiratory diseases and tuberculosis at Edinburgh University. With Scotland swept by an epidemic of the “white plague”, he found himself in charge of 400 tuberculosis beds in the Scottish capital and put together a team of five doctors and two bacteriologists to seek a cure for the disease. They became known as the Edinburgh Group.

Their breakthrough came when they discovered three drugs that had shown some success separately in treatment had a 100% success rate when used together. By 1958, they had eradicated the disease in Scotland but the medical world remained sceptical. With the backing of the Pasteur Institute in Paris, they organised a 23-country trial, the success of which led to widespread use of the treatment in countries that could access the drugs.

In recent years, TB has begun to spread again, partly due to increased air travel, more drug-resistant strains of the disease, insufficient aid and what Sir John called “bad doctoring by ignorant or unscrupulous doctors in countries such as India. We showed (in the 1950s) that if you give patients all three drugs to begin with, the disease won’t become drug-resistant. They have got the drugs in India, but a significant number of doctors are making money. They are either ignorant or just don’t bother and may give just one drug.”

In the past few years, on average, around 400 people still contract TB in Scotland, about half of them in Glasgow, with around 50 fatalities annually here as a whole.

After bullets from a shoot-out during the 1916 Easter Rising hit his nursery school, his parents decided he should be educated in England. He studied medicine at Cambridge University, then at the medical school of St Thomas’s Hospital, London, qualifying as a doctor in 1937. Between 1937 and the outbreak of war in 1939, he held junior posts at the same hospital and was admitted to the Royal College of Physicians.

When war broke out, he volunteered for the Royal Army Medical Corps and served in France, Egypt, Eritrea, Greece, Malta and Germany. In the run-up to Dunkirk, and under heavy shellfire, he tended horrific injuries after the Luftwaffe bombed three allied troop or ammunition trains near Rennes. “I was back in Southampton before I got the chance to wash the blood off,” he said.

From 1947-52, he worked part-time at London’s Brompton Hospital, doing trials on the antibiotic streptomycin, which would later become part of his triple-drug treatment for tuberculosis, and part-time as a lecturer at the Postgraduate School of Medicine in Hammersmith Hospital. During that period, he saw the birth of the National Health Service and, through his work, helped to nurture it while many doctors, outraged at becoming “state employees”, were strongly opposed.

When he arrived in Edinburgh in 1952 to take the chair of respiratory diseases and tuberculosis, with a plummy Oxbridge accent having long since replaced his native Irish brogue, a Scottish colleague jokingly told him: “Best keep your mouth shut for three months.” He remained in the post until his retirement in 1977, the year he was knighted.

During his time in the job, he was also dean of the Faculty of Medicine (1963-66) and vice-principal of the university (1969-71, a time of considerable student unrest). From 1973-76, he was president of the Royal College of Physicians of Edinburgh.

In 1995, he was awarded the Edinburgh Medal, given to men and women of science and technology judged to have made a significant contribution to humanity. In 2006, John Barrett, LibDem MP for Edinburgh West, launched a campaign to win international recognition for Sir John and his work in combating TB. “The work of Sir John has undoubtedly saved millions of lives worldwide,” Mr Barrett said.

Until shortly before his death, Sir John, along with his wife, remained deeply committed to the anti-tobacco campaign, notably through ASH Scotland, the group he jointly founded in 1973 with Oxford cancer epidemiologist Sir Richard Doll, one of the first scientists to link smoking with lung cancer.

Sir John Crofton, who died peacefully in Edinburgh, is survived by his wife, Lady Eileen, five children and 11 grandchildren.