The Conservatives' proposed revamp of the way people pay for social care has been criticised by an ex-government adviser and opposition parties.
There is universal acknowledgement that the system was overdue for reform, as social services in England can no longer finance rising demand.
The plans will see many more people paying for more of their home care.
Concerns have been led by former government advisor Sir Andrew Dilnot who proposed a cap on costs in 2011.
Sir Andrew criticised the decision to abandon the cap idea and said the changes would leave elderly people "helpless" until their assets reach £100,000.
Labour and the Liberal Democrats also attacked the plans, but Prime Minister Theresa May said the reforms were essential to ensure fairness "across the generations" and long-term sustainability of the social care system.
Under the system that had been due for implementation in 2020 nobody would have to pay more than £72,000 towards the cost of social care they receive at home.
People who have assets of more than £23,250 have to pay for all their care, those with assets of between £14,250 and £23,250 would get some help and below that all care is funded.
Under the new Conservative plans nobody who has assets of less than £100,000 would have to pay for care. But crucially, for the first time in the case of people being cared for in their own home, that calculation includes the value of their house. If their assets are above £100,000 they will have to pay until their value reaches that cut-off point.
The Conservatives have said nobody will have to sell their house in their lifetime, or that of a surviving partner, but ultimately care costs would be taken from their estate.
Mrs May said it would remove the worry that people would have to sell their homes while still alive, or see their savings dwindle to virtually nothing.
However Sir Andrew said the changes would leave people unable to plan for the future.
"There's nothing you can do to protect yourself against care costs, you can't insure it because the private sector won't insure it, and by refusing to implement the cap that Conservatives are now saying they're not going to provide social insurance for it," he told the BBC Radio 4 Today programme.
"So people will be left helpless knowing that what will happen is if they're unlucky enough to suffer the need for care costs, they'll be entirely on their own until they're down to the last £100,000, all of their wealth including their house.
"The analogy is a bit like saying to somebody you can't insure your house against burning down, if it does burn down then you're completely on your own, you have to pay for all of it until you're down to the last £100,000 of all your assets and income."
Solution desperately needed
Chris Ham, chief executive of The King's Fund health think tank, described the Conservative plans as "deeply disappointing".
"Instead of fundamental reform, these proposals involve tinkering with a broken system and do not provide the sustainable solution that is desperately needed."
Labour leader Jeremy Corbyn accused the Conservatives of "forcing those who need social care to pay for it with their homes". Speaking on the BBC Radio 2 Jeremy Vine Show he labelled the policy a "dementia tax".
Liberal Democrat health spokesman Norman Lamb, said "elderly people the length of Britain will shudder at these care cost proposals".
He said: "Many elderly people currently will face the cruel situation of having to sell their home when they die to fund residential care home costs.
"Now the frail and elderly receiving care in their own home will face what is a 'Personal Death Tax' charged against their home. And the more help you need, the more Theresa May will snatch away when you die."