Civil servants are to be balloted for strikes against the cap on public sector pay, the Public and Commercial Services union has announced.
Members of the PCS will vote in the coming weeks on whether to launch a campaign of industrial action.
The union said Civil Service pay had fallen by between £2,000 and £3,500 in real terms from 2010 to 2016 because of the Government's pay policy.
PCS officials said there was "escalating chaos" in the Government over the future of the cap, which is holding down pay rises for public sector workers at 1 per cent.
The union demanded that the cap is scrapped and replaced with pay rises of at least 5 per cent for all public sector workers.
The Government has come under increasing pressure to lift the limit on wages and there have been reports Theresa May is drawing up plans to discard the limit.
On Monday, a Downing Street spokeswoman refused to deny the claims, saying of public sector workers: "We recognise the sacrifice they are making".
Scottish first minister Nicola Sturgeon on Tuesday announced that Hollyrood would scrap the cap and future public sector wages would rise based on the cost of living.
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