Nottingham City Council is to take a dispute with its staff over incremental pay rises to the Supreme Court.
The 600 workers recently won their case when they appealed against a ruling over the council's freeze on annual payments received as staff move up the salary scales.
In an email sent to staff this week, the Labour-run council says it acted to prevent jobs being cut when it introduced the freeze in 2011.
But unions representing the staff condemned the decision to continue the legal fight over their claim that their member's contracts were broken.
They condemn the Labour-run council’s email as ‘disturbing’, and say that to link the settlement of back payments to possible redundancies is ‘intimidating’ and ‘a misrepresentation’.
The council says the freeze has saved the equivalent of about 1,000 full-time jobs and 'significant cuts to services and job losses' would have been unavoidable if it had not been introduced.
The council's email said: 'We are extremely disappointed with the Court of Appeal’s decision, which would result in a major additional cost to the council at a time when budgets are under huge pressure as a result of government cuts.
'As the financial impact of this judgement would be significant, an appeal against the decision is being lodged by the council.'
The letter from the unions Unison, GMB and Unite was copied to the city's Labour councillors and says the council should draw on its reserves to make compensatory one-off payments to the staff.
It says: 'Rather than acknowledge that the council did indeed breach our members’ contracts, the council has attempted to disparage and apportion blame to the trade unions for simply protecting their members’ legal rights in bringing a legitimate claim to the courts, which has been proven correct on two occasions.'
Read our feature exploring why the right to an automatic pay rise is disappearing in local government.