The study, published in The Lancet, found half the deaths from cancer in 2019 – more than 4.5 million people – were due to avoidable risk factors, such as tobacco, alcohol, obesity, pollution, unhealthy diets or occupational exposure to harmful elements such as asbestos.

Half of all male deaths from cancer, and more than a third in women, stem from these potentially preventable sources.

The clearest risk factor was tobacco, by a country mile ahead of the second, alcohol, and the third, high body mass index.

Despite the fact that these risk factors are well known to oncologists and the public, researchers say that deaths associated with these preventable factors have increased by 20 per cent in the last decade.

Metabolic risks accounted for the largest percentage of increase in cancer deaths and ill health, with deaths increasing by 34.7 per cent.

Cancer was seen as a chronic disease of developed countries but was on the rise in developing countries – as a country develops, it evolves from a pattern of infectious diseases to a pattern of chronic diseases.