With 280,000 people diagnosed with diabetes annually in Britain, the disease is becoming a "national health emergency", risking unsustainable strain on health services, Charity Diabetes UK said on Monday.
The charity said 738 people each day are told that they have type 2 diabetes, which is linked to being overweight.
"This clearly shows the frightening scale of what is fast becoming a national health emergency," the charity's Chief Executive Barbara Young said, warning of a strain to health services and disastrous consequences for patients.
Health authorities advise healthy eating and exercise to prevent developing the condition. Over a third of the British population have borderline diabetes and nearly four million people in Britain suffer from the condition, the charity said.
Almost a quarter of those aged over 15 in Britain were obese in 2012, according to the Organisation for Economic Co-operation and Development, compared to an average of 18.4 percent across the group of 34 wealthy countries.