A gigantic study - a quarter of a million commuters studied for five years, with things like smoking and weight taken into account has revealed that cycling has an extraordinary protective effect against cancer and heart disease.

The study of 264,337 people, published in the British Medical Journal, revealed that cycling is linked to a 45 per cent lower risk of cancer and 46 per cent less chance of heart disease, compared with driving or taking public transport.

Walking to work was found to reduce the chance of heart disease by 27 per cent, but there was no link with a lower risk of cancer or premature death. And in fact if you walk and get cancer, you have a higher chance of dying from the cancer, whereas if you cycle, your chance of dying is way lower.

Lars Bo Andersen, a professor at the Western Norwegian University of Applied Sciences, who was not directly involved in the research but wrote a commentary on it in the BMJ, said its findings "are a clear call for political action on active commuting", saying this had the potential to significantly improve public health by reducing rates of chronic disease.

"A shift from cars to more active modes of travel will also decrease traffic in congested city centres and help reduce air pollution, with further benefits for health," he said.

Many reports in newspapers but the graph in this report is particularly vivid in showing the health effects of cycling.

It is now urgently necessary that safe, protected cycling infrastructure be built so that all journeys under 3 miles/5km (20 minutes' pleasant cycle) can be made by bicycle.