The largest UK civil service union is balloting 280,000 workers in 200 Government departments and agencies about a planned strike action for 31st January, the deadline day for self-assessment tax forms.

The Public and Commercial Services Union (PCS) said its workers were angry about compulsory job losses, below-inflation pay offers and outsourcing of much of their work to commercial agencies and consultants, representing a saving and investment to the Government but uncertain times for them.

However, the Cabinet Office commented that the civil service “had to change” to meet expectations and that it had to represent a sound UK investment to its citizens.

“Chancellor Gordon Brown is saying that we can produce more with less public servants,” said PCS general secretary Mark Serwotka. “What he isn’t telling the taxpayer is that services will worsen if there are job cuts in the civil service.

“We have been negotiating with the Cabinet Office for two years and all we have seen is tens of thousands of public sector jobs go while private sector consultants rake in huge profits as part of their ever-increasing UK investment in Government activity.”

Cabinet secretary Sir Gus O’Donnell wrote to Serwotka about the issue, saying: “While departments and the civil service as a whole will continue to do all we can to avoid compulsory redundancy, we cannot provide any guarantee in that respect.”

Cabinet Office minister Pat McFadden said: “There is absolutely no need for a strike.”