There are more than 850,000 people walking around with undiagnosed diabetes in this country, but equally worrying is that many of the 2.9 million people who have it and know about it are not properly managing the condition.

Now a charity is warning that this failure could lead to a 'public health disaster' and urging the government to step in with support programmes, along with ongoing medical care and education.

Barbara Young, chief executive of Diabetes UK, said: 'Given that diabetes is serious and can lead to early death if not supported to manage their condition, it is extremely worrying that so few people have it under control.

'When you consider that there are now three million people diagnosed with diabetes and this number is rising quickly, the fact that so many of them do not have good control over their diabetes means that unless something changes we face a public health disaster. Whether these people have high blood glucose levels, blood pressure or cholesterol, they are at increased risk of diabetes-related complications such as heart disease, amputation, and stroke.'

The charity's analysis of National Diabetes Audit figures showed that 19.9pc of people with Type 1 or Type 2 diabetes in England meet health targets for blood glucose, blood pressure and cholesterol levels, with the number even lower in Wales at 18.5pc.

Out of those in England with Type 1 diabetes, which requires the daily administration of insulin, only 11.4pc are meeting the recommended levels.

Prof Mike Sampson, left, a diabetes consultant at the Norfolk and Norwich University Hospital, said warnings such as this from Diabetes UK were a helpful reminder of the scale of the problem in this country.

'There are 45,000 people with diabetes in Norfolk, both diagnosed and undiagnosed. By 2030 there will be about 70,000 people. We know that 20 years ago there were only 17,000 so there is a huge increase in the number of people with diabetes which puts pressure on health systems, in general practice and hospitals. It's going to get increasingly difficult to manage all of these people and to help them and help primary care to deliver all of these targets.'

Currently only 54pc of people with diabetes in England get the nine annual checks recommended nationally to prevent future problems.

Prof Sampson said the Norfolk area was above the national average for the number of checks carried out, which was a positive.

'The big issue is there are going to be so many more people with diabetes over the next 10 and 20 years. The question is whether the resources are going to be there to cope with it,' he said.

'One of the problems of diabetes is that it affects so many different areas of the health system – in-patient care, pregnancy, eye problems, circulatory disease, foot care and renal programmes. It is often difficult to remember how big the problem is and it's helpful to have this sort of reminder of what a huge public health problem diabetes is.'

Some 24,000 people with diabetes die early every year in England and Wales, according to Diabetes UK.

The NHS spends about £10bn a year on diabetes, some 10pc of its entire budget, the charity added, with 80pc of that going on treating complications that could have been prevented in many cases.

Do you have a health story for the Norwich Evening News? Call reporter Adam Gretton on 01603 772419 or email adam.gretton@archant.co.uk