Diabetes costs the NHS £1 million an hour, according to a new report.
Around 10% of the NHS budget each year is spent on treating diabetes and complications caused by the disease, such as blindness, kidney failure, stroke, heart disease and limb amputation.
The statistics were drawn up by the charity Diabetes UK using data from the Department of Health and NHS spend in 2007/08.
The charity's report showed that 10% of the NHS budget went on diabetes - equivalent to £9 billion a year or £1 million an hour.
One in 10 people in UK hospitals have diabetes and 60% of hospital inpatients with diabetes have been admitted as emergencies.
There are currently two million people diagnosed with Type 2 diabetes in the UK, which is linked to lifestyle factors like obesity, while a further 500,000 are thought to be undiagnosed. Around 250,000 people in the UK also have Type 1 diabetes, which often develops in childhood.
The report - called Silent Assassin - highlighted how the problem was set to get worse.
"It is estimated that by 2025 there will be more than four million people with diabetes in the UK," it said.
"Most of these cases will be Type 2 diabetes, attributable to an ageing population and rapidly rising numbers of overweight and obese people."
Douglas Smallwood, chief executive of Diabetes UK, said: "Type 2 diabetes can remain undetected for 10 years or more before someone is diagnosed. It really is a silent assassin - more than 500,000 people have the condition but do not even know it and by the time they are diagnosed with Type 2 diabetes, 50% of people are found to have started developing complications."
