Phil Hope, the Labour MP for Corby, and the Government's care services minister, announced he wanted GPs to help detect early-onset dementia as part of attempts to transform the system of care for sufferers as the population of the UK gets older.

But the Local Medical Committee (LMC) in Northamptonshire suggested lack of diagnoses could be more down to scepticism about what could be done for mild sufferers of some types of dementia rather than a lack of training.

Dr Anthony Pickering, a GP in Denton and chairman of the LMC, said: "GPs are sometimes perfectly aware of cases but they don't always record them as there's not a whole lot they can do about it.

"The reason is that NICE have said that the drugs for it can be only used for moderate to severe cases.

"Those with a relatively small need get proportionately little assistance."

Dr Pickering said he therefore questioned the accuracy of the Government's statistics on how many cases of dementia GPs were already diagnosing.

But, talking to the Chron yesterday, Mr Hope defended the usefulness of training GPs to spot early signs, which will form part of a dementia strategy to be revealed next year which will raise dementia to the level of priority of cancer and heart disease.

He said: "It's even more important that GPs detect early-onset dementia because the earlier you intervene the more effective you can be with either health or social care."

Mr Hope added that his planned memory clinics, which he hoped to roll out to every large town in the country, are one of the ways he hoped to help people with non-severe dementia.

He was also backed by the local branch of the Alzheimer's Society, who welcomed his plan to train GPs.

Gill Shadbolt, manager of the Northampton and District Branch of the Alzheimer's Society, said: "Although there is no cure for Alzheimer's, the earlier it is diagnosed the earlier the patient can access information and support.

"It is devastating when they are first told what is wrong but at least then they can start to come to terms with it and start to get help."