Diabetics in England are facing a postcode lottery, with thousands of sufferers going undiagnosed, a report has found.
The NHS Health Check programme failed to diagnose type 2 diabetes in 9,500 cases in the 2011/12 financial year because they were not tested, according to the report by Diabetes UK.
The report, entitled Let's Get it Right, found that the health check was supposed to be given to all people in the target age group of 40 to 74, but in practice there were huge regional discrepancies.
In areas like Liverpool and Greenwich thousands of people were checked during the 12-month period while in other areas no-one was checked.
There were also many cases of type 2 diabetes that could have been prevented by identifying people at high risk and giving them support to reduce that risk, the report said.
Diabetes UK chief executive Barbara Young said a public awareness campaign was needed so that people aged 40 to 74 knew they are entitled to the check, which also tests for risk of heart disease, stroke and kidney failure.
"The failure to deliver the NHS Health Check has potentially dire consequences for the state of diabetes care in this country," Ms Young said.
"It is vital that people with type 2 diabetes are diagnosed as early as possible to reduce their risk of developing complications and we are concerned that the estimated 9,500 people who missed being diagnosed last year are at increased risk of amputation, blindness, kidney failure and stroke.
"The fact that there are some places where not a single person has been offered a check is appalling."