Last year, speakers at the annual American Society of Clinical Oncology meeting – the most eminent cancer conference in the world – came with a dire warning.

Rates of colorectal cancer were rapidly increasing in the under 40s, they said, so much so that cases were expected to double in this age group by 2030, and the disease was set to become the number one source of cancer deaths in 20-to 49-year-olds by the end of the decade.

The Telegraph London