Union leaders have reacted with fury after Chancellor Rishi Sunak imposed a pay freeze on at least 1.3 million public sector workers.
The GMB union said it had fought a public sector pay cap before "and we busted it", while the civil service and rail unions warned of strike action.
Frontline NHS staff and lower paid workers will get pay rises, Mr Sunak said in Wednesday's Spending Review.
But Mr Sunak said rises for others in the public sector were being "paused."
This includes civil servants, teachers, police, firefighters, the armed forces, and council staff
Rehana Azam, national officer of the GMB union, said the freeze "will hit key workers who have risked everything during the pandemic".
"This attempt to divide and rule will put him on a direct collision course with public service workers, and he should know that we fought the public sector pay cap before and we busted it," she said.
"GMB will not accept more pay cuts for our members at a time when the whole country is relying on them.
Mark Serwotka, general secretary of the Public and Commercial Services union (PCS) said: "Civil servants and other public sector staff will feel a deep sense of betrayal at today's pay freeze.
"Despite keeping the country running during the Covid crisis, supplying Universal Credit and helping businesses access the furlough scheme, the chancellor has justified a pay freeze by pointing to lower wages in the private sector."
He said the news "has intensified long-standing anger at a decade of pay restraint and increased the likelihood of industrial unrest in the public sector."
Mick Cash, leader of the Rail, Maritime and Transport union (RMT), also warned that members will "have no hesitation in taking strike action", while Unison general secretary Dave Prentis said: "This is austerity, plain and simple."
Other union leaders also lined up to condemn the freeze, including Unite, Prospect, and the Fire Brigades Union.
The Treasury has estimated that the pay announcement will directly affect 1.3 million workers, less than 25% of the total number of 5.5 million in the public sector.
However, that figure mainly covers people working for central government. The total rise could be much higher if local government and devolved pay agreements are frozen.
In his Spending Review, Mr Sunak highlighted a disparity between public sector and private sector wages, adding he "cannot justify a significant, across-the-board" pay increase for all public sector workers in the circumstances.
"Instead, we are targeting our resources at those who need it most," he said.
He said 2.1 million public sector workers earning below the median wage of £24,000 were "guaranteed a pay rise of at least £250".
More than a million NHS workers will also get a raise, he said.
Meanwhile, the National Living Wage will increase by 2.2% - or 19p - to £8.91 an hour, with the rate extended to 23 and 24 year olds for the first time.