The Public and Commercial Services (PCS) union won a legal battle on Monday to stop government cuts to civil servants' redundancy pay.
Action by the union, which represents some 270,000 civil servants, comes against a backdrop of growing worker unrest over state spending cuts to rein in Britain's record budget deficit and private sector efforts to save money after the 2008 financial crisis hit profits.
"Following a two-day judicial review (the court) ruled today that the previous government acted unlawfully when it introduced, without PCS's agreement, a new redundancy scheme reducing the rights staff had accrued over time," the union said in a statement, referring to the outgoing Labour government.
The Conservative Party and the Liberal Democrats are currently in talks to thrash out a coalition or power sharing agreement after Thursday's general election saw the Conservatives win the most seats but not enough to rule alone.
Whoever leads the next government is expected to make deep spending cuts to tackle a deficit running at more than 11 percent of GDP, a shortfall that has unnerved financial markets and could threaten Britain's AAA credit rating.
In March, about 250,000 civil servants walked out in a two-day strike over redundancy pay, the same month British Airways cabin crew left work in a high-profile protest over pay. Rail workers also voted to strike, but the move was blocked by the rail infrastructure operator Network Rail.