Hundreds of older people may be living with undiagnosed dementia in Worcester, figures suggest.

The Alzheimer’s Society says that, while diagnosis rates for the condition have improved in recent years, the level of detection varies drastically across England – with the disease now thought to be the country's biggest killer.

NHS Digital data shows that 818 people aged 65 or over in Worcester had a recorded dementia diagnosis in September.

But estimates in the same data, based on the local population, suggest the real number could be 1,414, meaning around 596 pensioners may have dementia without it being recorded by their doctor.

Office for National Statistics figures released earlier this year revealed that dementia and Alzheimer’s accounted for around one in eight deaths registered in England and Wales last year – the leading cause.

The NHS figures were collected in response to former prime minister David Cameron’s Challenge on Dementia 2020, which included a target for at least two-thirds of people with dementia to be diagnosed.

The numbers show that about 58% of expected dementia sufferers in Worcester were diagnosed in September, well short of the target. It was also the same as the previous September.

Across England, 462,000 older people had recorded dementia in September – around 69% of those estimated to have it. But the detection rate varied dramatically throughout the country – Enfield in London had a recorded diagnosis rate of 93%, while in South Hams in Devon, it was just 43%.

Sally Copley, Alzheimer’s Society’s director of policy and campaigns, said: “The number of people with dementia is set to double over the next two decades, and as data shows, it’s still the UK’s biggest killer."

A Department of Health and Social Care spokeswoman said: “More people are being diagnosed with dementia than ever before, and we are committed to improving this further with better access to care and support, increasing public awareness and putting millions of pounds of funding into dementia research.”