It's estimated there are around 620,000 people in England with dementia. Prime minister David Cameron says fighting the disease is a personal priority and doctors in England have been encouraged to proactively identify people with early stage dementia. The PM says that an early diagnosis allows families to prepare for the care of a relative, but others argue there's no treatment for such a diagnosis and no robust evidence to justify a process that might lead to harm. Deborah Cohen hears from doctors who are concerned the drive to raise diagnosis rates is leading to people being misdiagnosed. The Government has also pledged millions of pounds to help make England "the best place in the world to undertake research into dementia and other neuro-degenerative diseases". Scientists leading the research say they are making progress to find tests which could identify people at risk from the disease and develop a cure. But other researchers say money is being wasted because current directions in drug development are following the same path as those of the past which have ended in failure. Producer: Paul Grant.