The NHS is wasting billions of pounds of public money by failing to tackle diabetes early enough, experts have warned.
The disease costs the health service nearly £10 billion a year, but the vast majority of this cash is spent on tackling complications that arise from the illness such as kidney damage.
The charity Diabetes UK accused health bosses of "failing to learn" that early intervention can save taxpayers' money and improve the lives of millions of Britons living with the illness.
Barbara Young, Diabetes UK c hief executive, said: "The NHS is spending an eye-watering amount on diabetes but the money isn't being used effectively, which is running up a huge bill for the future.
"This report shows how dealing with problems early, such as by improved inpatient care and effective care planning, costs could be greatly reduced and more people would live longer and healthier lives.
"Too often, the focus is on cutting costs in the short-term such as by cutting diabetes specialist nurses, restricting access to blood glucose test strips and poorly planned transferrals to primary care. But this is making it difficult for those with diabetes to manage the condition and is offering poor value for money for taxpayers."
She warned that at a time of tightening budgets and when the number of people diagnosed with diabetes is spiralling, the " current approach is unsustainable".
In a new report, The Cost of Diabetes, the charity accused health chiefs of failing to implement measures that can slash costs and improve care for diabetes patients.
The NHS spends £9.9 billion a year tackling the illness, and that bill is set to rise as growing numbers are diagnosed with the condition.
But just £2.1 billion is spent on treating the actual illness itself, while £7.7 billion goes on addressing complications that could have been prevented if the patient had received good healthcare in the first place, the charity said.
Those who are diagnosed late or do not receive timely care can find themselves having to spend extra days in hospital and suffering from kidney and nerve damage as a knock-on effect, running up huge bills for the NHS.
While vast amounts of money is being ploughed into diabetes treatment, it is too often used ineffectively, the charity warns.
The report sets out a series of measures it claims will save the health service billions and improve patient care.
It claims that better programmes educating on how to manage the condition can save £2,200 a patient while a reduction in foot amputations - a traumatic and expensive complication of diabetes - could save hundreds of millions of pounds a year.
Diabetes is a chronic illness that causes a person's blood sugar level to become too high.
In the long term it can damage a sufferer's eyes, heart, nerves, feet and kidneys - leaving many dependent on gruelling and costly dialysis machines.
With the numb er of people with diabetes estimated to hit five million by 2025, Diabetes UK warned the NHS needs to quickly improve its care before the bill to the public purse becomes unmanageable.
Ms Young said: "With the NHS operating in a period of flat budgets and with the number of people with diabetes rapidly increasing, it is really important that trusts and commissioners implement these changes because the current approach is unsustainable and is having a significant impact on NHS resources.
"One of the benefits of a national system for health ought to be fast and universal adoption of good practice but the NHS is failing to capitalise on this in the case of diabetes care."
Professor Jonathan Valabhji, national clinical director for obesity and diabetes at NHS England, said: "There are opportunities to improve outcomes for people with diabetes as well as deliver savings for the NHS. We need to seize them.
"More personal care planning and better integration of GP and specialist services may well deliver real benefits."