Less than half of those suffering from dementia are actually diagnosed, according to Alzheimer's Society.
New NHS statistics say that nearly 249,463 people in England have been diagnosed with the disease while, according to the charity, some 575,000 actually have the condition.
Andrew Chidgey, head of policy and campaigns at the Alzheimer's Society, says that the low diagnosis rate underlines the problem of those with dementia not visiting their GP and diagnoses not being made even when they do.
"It is clear that there is a shortfall and we must increase understanding of dementia amongst the public and GPs to ensure a swift and timely diagnosis," he adds.
Mr Chidgey advises that individuals should visit their doctor if their forgetfulness begins to affect their functioning in everyday life.
Meanwhile, the BBC reports that Kay Hamilton, the widow of the 15th Duke of Hamilton who died of vascular dementia earlier this year, is spearheading a £1.5 million project by Alzheimer Scotland to put a specialist dementia nurse on every health board in the country.
Find the nearest Barchester nursing home.