Jeremy Corbyn has written to the Prime Minister calling for urgent talks on social care funding.
The Labour leader is urging Theresa May to provide "emergency top-up funding" to protect elderly and vulnerable people at Christmas.
In the letter, Mr Corbyn writes: "After £4.6 billion of cuts to social care budgets since 2010, more than a million elderly people are not getting the care they need.
"Social care is in a deepening crisis which threatens the well-being, dignity and lives of hundreds of thousands of older people.
"The social care system is breaking down from lack of support. I hope you will be prepared to discuss both emergency support for social care to tide services over until April, as well as longer-term solutions to the funding and restructuring of social care provision.
"Relying on the council tax to plug the shortfall will lead to a postcode lottery and shift the cost on to hard-pressed council taxpayers. The Government must take responsibility."
Mr Corbyn proposes an urgent meeting at "the highest level" to discuss emergency support for social care and to look at more far-reaching solutions.
The letter concludes: "There is an opportunity to avert a crisis this winter. Will your Government agree to take it?"
A Conservative Party spokesman said: "Labour have no credibility at all when it comes to social care.
"They had 13 years to find a long-term solution and totally failed to do so.
"Ahead of the 2015 election, the Labour Party promised no additional money would be spent on social care.
"Now they suggest raising corporation tax, a pot of money they have already promised to spend on higher welfare payments, scrapping university tuition fees and ending public sector pay restraint."