The Government said it was "disappointing" that the PCS union is planning three months of industrial action, including a huge strike on Budget day.
A Cabinet Office spokesman said: "It is disappointing that, yet again, the PCS insist on pushing for futile action which benefits no-one, and damages the services they deliver to the public."
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The chancellor now faces the prospect of forming a minority government or calling for a snap election.
The 73-year-old said a return is unlikely "given the politicised atmosphere that seems to have afflicted our set."
Chancellor Philip Hammond said the UK will make a financial proposal to the EU in the next three-and-a-half weeks.