Nearly one million people are unaware that they have diabetes, Public Health England (PHE) has said.

The new Diabetes Prevalence Model, produced by PHE National Cardiovascular Intelligence Network (NCVIN) and launched today at the PHE Conference at Warwick University, estimates that one in four people with diabetes, an estimated 940,000, are unaware of their condition.

In total, the model says 3.8 million people in England aged over 16 had diabetes in 2015, around 9% of the adult population.

Of that, approximately 90% of cases are type 2, the risk of which is increased by being overweight.

This type of diabetes is largely preventable or manageable by lifestylechanges, which also provides additional benefits for health and wellbeing.

The disease can lead to serious complications including foot amputation and kidney disease, and is associated with an increased risk of stroke and heart attack.

John Newton, chief knowledge officer at PHE, said: “The number of people with diabetes has been steadily increasing and tackling it is fundamental to the sustainable future of the NHS.

“Diabetes can be an extremely serious disease for those that have it and treating it and its complications costs the NHS almost £10 billion a year.

“Developing Type 2 diabetes is not an inevitable part of aging, we have an opportunity through public health to reverse this trend and safeguard the health of the nation and the future of the NHS.”

The model also found that the proportion of people who have diabetes increases with age.

Some 9% of people aged 45 to 54 have diabetes, but for people over 75 the figure increases to 23.8%.

Diabetes was also found to be more common in men at 9.6%, compared with 7.6% women.

Based on current population trends, by 2035 4.9 million people will have diabetes.

Chris Askew, Chief Executive of Diabetes UK, said: “These new estimates clearly show the scale of diabetes and the huge impact on people living with the condition.

“Too often they only find out they have the disease after they have developed serious complications, such as heart or kidney disease, or foot problems which can lead to amputations.

“Avoiding or delaying such devastating complications depends on people getting diagnosed earlier, so they get help and support to manage their condition well. We urge people over 40 to attend their NHS Health Check when invited.

“We also want people to take the necessary steps to find out their risk of developing type 2 diabetes, such as using Diabetes UK’s online Know Your Risk tool.”

Type 2 diabetes currently costs the NHS £8.8 billion each year and tackling the rise in the disease is vital to the sustainable future of the health service.