Free personal care will be introduced so the frailest can be cared for in their own homes, Prime Minister Gordon Brown has pledged.
Under what is being dubbed the National Care Service, some 350,000 people with "the highest needs" would receive home care regardless of personal wealth.
Currently anyone with savings over £23,500 receives no state assistance.
Ministers hope to implement the scheme in England by mid-2010. A general election must be held by early June.
Addressing the Labour party conference, Mr Brown also promised results within one week for those with suspected cancer.
This enhances a pledge unveiled at the weekend in which those with less clear cut cases of suspected cancer would receive diagnostic tests within two weeks of seeing their GP.
Mr Brown said in some cases people would receive testing and results on the same day.
Staying at home
He also elaborated on manifesto plans to overhaul the current system of social care for the elderly, which is seen by many as punishing those on modest incomes who have saved for their old age.
It will be essential that councils are properly funded to provide this care so that there is not an incentive for them to push older people into care homes
Andrew Harrop Age Concern and Help the Aged
The National Care Service will bring together the NHS and local authorities which currently provide social services, Mr Brown said.
The proposals for personal care will affect some 350,000 people in England who require assistance with every aspect of day-to-day living - from dressing to cooking. It would not apply to those already in residential care, but in principle help people to remain in their homes.
A total of £400 million a year will be taken from low priority areas of the NHS budget, including marketing and communications, to help pay for the plan.
"Today more and more people see their parents and grandparents suffering from conditions like Alzheimer's and dementia, and they see their dignity diminish," Mr Brown said.
"And for too many families the challenge of coping with the heartbreak is made worse by the costs of getting support.
The people who face the greatest burden are too often those on middle incomes who have savings which will last a year or two but then they will see their savings slip away
"The people who face the greatest burden are too often those on middle incomes who have savings which will last a year or two but then they will see their savings slip away.
"The best starting point for our National Care Service is therefore to help the elderly to get the amenities to do what they want most to do: to receive care and to stay in their own homes as long as possible
"So I can say today that for those with the highest needs we will now offer in their own homes free personal care."
The proposals relate only to England, and appear to mirror those introduced under a devolved government in Scotland: here there is free social care, but the threshold is set relatively high to include only those with the most severe needs.
Andrew Harrop, head of policy for Age Concern and Help the Aged, said he welcomed the commitment to free care.
But he stressed: "It will be essential that councils are properly funded to provide this care so that there is not an incentive for them to push older people into care homes or claim that their needs are not critical enough to warrant free care at home."
Neil Hunt, chief executive of the Alzheimer's Society, said: "A commitment to free personal care for people with the most complex needs living in their own homes sounds like a promising development.
"We now need to hear the substance behind the sound bite. What is meant by 'highest needs' and what criteria will be used to judge this?"
The chief executive of the King's Fund, Niall Dickson, said "the devil will be in the detail".
"On the face of it targeting those in greatest need has a strong appeal but as ever when you do something for one part of the system there must be a danger of creating perverse incentives.
"Assuming the extra funds from central government won't be ring fenced there is a danger that local authorities will have a perverse incentive to encourage people into residential care where many older people will still have to pay out of their own pockets.
"We will also have to be clear how this new announcement fits with the proposals in the social care Green Paper. The government spent more than a year developing the options, and is now in the middle of a major consultation, yet this idea was not among them.
"It does seem slightly odd to produce this rabbit from a hat just as the debate is getting under way."
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