Sharper than expected cuts to jobs and services in Derby could affect the city for generations, a union has warned.
Council leader Harvey Jennings revealed on Thursday budget cuts were to be "front loaded".
This means instead of four annual cuts of 7.1% as had been planned, the authority will have to reduce spending by 14.2% in the first 12 months.
Unison said this would hit services harder and the jobs would be lost to "our children and grandchildren".
Chancellor George Osborne announced the 7.1% annual funding cuts for local councils on Wednesday, as part of wide ranging savings designed to cut the country's deficit.
Mr Jennings said the Conservative-controlled authority now faced a "significant challenge" to find the extra savings but would try to protect services.
Moz Greenshields from the union, Unison, said: "I'm sure the people of Derby who are currently in receipt of services will be as concerned as my members are in providing those services at this news.
"What it means in Derby is that although departments have been looking at 30% cuts and budgeting on that basis - over a period of time. The front loading of those cuts will have a bigger impact at exactly the time the demand for services is going to increase."
She also said the news that 600 people had expressed an interest in voluntary redundancy was unwelcome.
"That is 600 jobs of people who are providing services to the people of Derby and those jobs are not just jobs for the people currently doing them but they are jobs for our children and grandchildren in the future".