The Government's reforms of the NHS will not tackle the growing demand from dementia sufferers, according to a new report.
The number of people with the condition is expected to soar as the population ages, with more than a million people diagnosed by 2021.
The number with undiagnosed dementia is also set to double to almost 600,000 by 2021.
Diagnosis rates currently stand at about 40% and a report out today warns that giving GPs control of commissioning services could cause even more problems.
The study, from the think-tank the Institute for Public Policy Research (IPPR), analysed services in London and found issues with the future commissioning of dementia care.
Fewer than one in three GPs in the capital said they were able to diagnose dementia or to provide sufficient help for sufferers, the report said.
It found particularly poor care for the over-80s and a lack of services for those from black and minority ethnic backgrounds.
Experts behind the study called for stronger links between health and social care to offer people with dementia optimal care.
They said dementia also needs to be seen as a priority, and local authorities should retain a role in scrutinising the care that is provided.
The NHS Commissioning Board, which will oversee how services are bought for patients, should ensure GPs are held directly accountable for the quality of dementia care they provide.
Further evidence is also needed on how providing early interventions for dementia can produce cost savings.
Rick Muir, associate director at the think-tank, said it was clear dementia care was inadequate and, at the same time, "GPs admit that they do not have the skills to deal with this growing care crisis.
"The health reforms which bring in new commissioning arrangements are an opportunity to ensure that the wedge between health and social care doesn't grow - leaving dementia sufferers stuck in the middle with inappropriate or inadequate levels of care.
"But at the moment it is far from clear that changes will rise to the challenge.
"It's essential under the new commissioning framework that both GPs and social care commissioners are held truly accountable, that good practice is driven forward and that joint working is supported.
"If this doesn't happen, many vulnerable elderly people will not get the care they need."
The report comes as Health Secretary Andrew Lansley said the NHS will not be able to meet the demands of people with long-term conditions such as diabetes and asthma unless it changes.
There will be a 252% increase in the number of over-65s with one or more such conditions by 2050, he said.
Almost one in three people currently have a long-term condition, such as asthma, heart and lung disease, arthritis, high blood pressure or diabetes.
Mr Lansley said the NHS needs to reform if it is to cope with the growing numbers, and offer support to keep people out of hospital, which also saves money.
But the head of the Royal College of Nursing (RCN) said Mr Lansley's reforms are leading to thousands of job cuts, including among nurses who specialise in long-term conditions.
Dr Peter Carter said the cuts will put vulnerable patients at risk and the reforms will cost billions.
A poll of 1,000 members of the public found almost two-thirds (65%) did not want GPs to extend their duties beyond caring for patients.
Asked the question: "The Government is proposing that doctors should not concentrate solely on medical matters, but should also take on a role in organising payments for hospital care. Do you agree or disagree with this change?", 27% agreed, 65% disagreed, 7% said they did not know.
Paul Evans, director of campaign group the NHS Support Federation, which commissioned the poll, said: "The public are joining in the unprecedented chorus of opposition to the NHS shake-up.
"It is the wrong idea at the wrong time and health staff, charities and health experts are set against them.
"The political heat is rising and the Government must recognise how unpopular these plans have become and change them.
"The public are waking up to the reality of the reforms, which will break up the NHS and put business motives at the heart of the service.
"At a time of severe cuts, these flawed reforms risk rising waiting lists, undermining patient care, huge unfairness and a waste of public funds."