Other councils could follow Tory-controlled Surrey in seeking huge hikes in tax, the leader of Theresa May's local authority has warned.
Simon Dudley, Conservative leader of the Royal Borough of Windsor and Maidenhead, said Surrey could be the "canary in a coal mine" signalling the difficulties facing other authorities.
Surrey plans to hold a referendum to allow it to raise council tax by 15%, claiming it has no choice in response to funding cuts and the crisis in social care.
"Surrey is, in my view, just a canary in a coal mine. There will be other local authorities that are faced with incredibly difficult decisions in terms of preserving broader council services or protecting the vulnerable," Mr Dudley said.
"Given the way there is a referendum cap on how a local authority can increase its council tax, they will be forced to go to their electorate and go through a very painful process of asking people to make difficult decisions."
Mr Dudley told the BBC Radio 4 Today programme that his authority was raising council tax by 3.95%, including the 3% increase allowed to fund social care.
He said: "We have in the region of 150,000 residents, yet 40% of everything our local authority spends it spends on adult social care for in the region of 2,500 of those residents to protect them, they are vulnerable.
"We want to spend that money, we will spend that money.
"But it gives you an idea of the importance of adult social care in the overall budgets of local authorities."
Asked if he had made his point to the Prime Minister, the MP for Maidenhead, he said: "I have previously indicated the pressure local authorities are under in terms of adult social care."
Explaining his plan on Thursday, Surrey County Council leader David Hodge said: "Demand for adult social care, learning disabilities and children's services is increasing every year.
"So I regret, despite us finding £450 million worth of savings from our annual budget, we have no choice but to propose this increase in council tax."
The move will add almost £200 to average Band D council tax bills in Surrey.
Councils wanting to raise tax by 5% or more must gain the support of voters in a referendum.
A Department for Communities and Local Government spokesman said: "The Government has protected local residents from high council tax rises by allowing local people to veto them through a council tax referendum.
"If the council sets this proposed budget, then the taxpayers of Surrey will have the final say in a referendum in May. We should trust the people."
A spokesman for Mrs May told a regular Westminster briefing: "The Government has given councils much greater freedom to decide how they spend their tax revenues so that they can best serve their local communities. Councils have been given the authority to raise the funds in their local area as they best see fit.
"Government has given extra funding for the issue of social care, but I would make the broader point that this isn't just about funding, as we have pointed out on several occasions; there are certain local authorities where, for instance, they have had no delayed discharges from hospital as a result of issues around social care.
"So, we want to see those sort of best practices deployed across local government."