By Ben Davies
BBC News Online political staff
Plans to cut more than 100,000 civil service jobs look set to trigger strike action hitting vital government services, BBC News Online has learned.
Mr Serwotka pledges to fight for his members
PCS boss Mark Serwotka, who represents many of the civil servants, said he would "rule nothing out" in the fight to save the jobs.
He said strike action was currently being looked at with an announcement due at next week's TUC conference.
Mr Serwotka said striking would show how vital public servants' work is.
"Maybe they'll see if they are not there doing their job they'll realise how much they miss them," he warned.
"That is why at the congress next week we will outline a very detailed campaign plan for the here and now, in the run up to the election and after the election as well.
"If we are not successful in this campaign the people who will suffer are the people of this country and that's the critical message we've got to work hard to get across."
Asked to clarify when strike action - which would require a ballot of PCS members - was on the cards he would only add: "That is something we are currently considering and we will be detailing our exact plans in that area at congress."
In his interview with BBC News Online Mr Serwotka said he thought the threat to civil service jobs would dominate the conference and he accused the government of putting vital services under threat just to display waste cutting credentials ahead of an election.
"It's clear I think to trade unionists that the government is playing politics with the Conservatives over who can be toughest on waste - when actually what it should be doing is recognising the incredible contribution that civil servants make to the running of this country," he said.
"If they make these job cuts the vulnerable will suffer whether they are pensioners, people who want driving tests, cars taxed, people who need passports, who go through our customs every day, they all need civil servants for frontline services."
Mr Serwotka said the government was trying to play on public perceptions that civil servants were "faceless bureaucrats" or "bowler-hatted Sir Humphreys".
But he argued the reality was that the job losses would have a huge political fallout costing an average of 150 jobs in every constituency and cause "chaos" in public services.
He added: "We don't claim there aren't any savings to be found anywhere - we can think of lots of efficiencies."
"We've pointed out that millions of pounds have been wasted in failed new technology projects done by the private sector, we've pointed out that if they talked to their workforce there are lots of ways they could do things better.
"Their approach seems to be they don't know anything and therefore we know what's best for them and 100,000 jobs are going to be taken off the payroll."
Mr Serwotka said under Labour had created 57,000 new civil service jobs in order to deliver its programmes.
"The question is why create the jobs in the first place if you then intend to cut not just the jobs you've created but double the amount," he said.