Eating broccoli or cauliflower at least once a week can dramatically reduce a man’s chances of developing the most dangerous form of prostate cancer, new research has shown.

Broccoli can slash the risk of an aggressive tumour by 45 per cent, according to the new study, and cauliflower can cut the risk by 52 per cent.

The scientists, led by experts at the US National Cancer Institute in Maryland, tracked 29,000 men over a four-year period.

But the results, published in the Journal of the National Cancer Institute, cast doubt on whether foods like tomatoes, which have been touted as having powerful anti-cancer properties, really have any effect on the disease.