Union leaders clashed with the Government tonight over the effect of a strike by civil servants.
The Public and Commercial Services union claimed more than 200,000 employees had walked out causing "widespread disruption" to services.
The union said court sittings were cancelled, jobcentres offered limited services, 2,000 driving tests called off, passport appointments hit and border controls at ports and airports disrupted.
But the Cabinet Office maintained that 81,000 PCS members were on strike, adding that 85% of civil servants were working normally.
Ministers said all jobcentres and benefits offices were open, border entry points were working normally and court services were being maintained, while HM Coastguard said only 15 staff of 1,227 were on strike.
Picket lines were mounted outside Government offices across the country as well as the House of Commons - the first protest of its kind in a generation.
The union said there had been "solid support" for the start of the 48-hour walkout held in protest at cuts to redundancy pay.
The union is protesting over changes to the civil service compensation scheme which it says will "rob" civil servants of up to a third of their entitlements - worth thousands of pounds - when they leave their jobs.
MPs warned there was "growing consternation" on the Labour backbenches over the dispute especially as it had flared so close to the election.
PCS general secretary Mark Serwotka said: "There has been a fantastic show of support for the strike action today with civil and public servants walking out across the UK. The government needs to stop burying its head in the sand and wake up to the scale of anger that has been generated by their plans to cut jobs on the cheap.
"Loyal civil servants face losing tens of thousands of pounds if they are forced out of their jobs. The Government is tearing up their contracts in front of their eyes, yet claims it can do nothing about bankers' bonuses because of contractual obligations. We expect support for the industrial action to grow and call on the Government to reach an negotiated agreement."
Cabinet Office Minister Tessa Jowell said: "More than 70% of PCS members have decided not to take part in today's action.
"Across the country services to the public are largely unaffected - all job centres and benefits offices are open, border entry points are working normally and court services are being maintained.
"Today's low turnout supports the view that after 18 months of negotiation and consultation the right deal on reforming the civil service compensation scheme has been reached. The changes have already been agreed with five of the six civil service unions.
"During the negotiating process, we responded to union concerns by ensuring additional protection for lower paid staff.
"This means that the vast majority of the 46% of civil servants who earn £20,000 or less will in fact be little affected by the changes. They can still get up to £60,000 - the same as before. This package brings the civil service more into line with the rest of the public sector and still offers more generous terms than much of the private sector."
At Bradford Crown Court, a case involving 20-year-old Muawaz Khalid and three teenagers charged with the murder of 63-year-old shopkeeper Gurmail Singh was affected by the strike.
The majority of the courts were not sitting or were holding administration days today, so the case was brought forward and dealt with last Friday, where a plea and case management hearing was listed for June 18 and a provisional trial date set for August 31.
The PCS will hold a march and rally in Central London tomorrow to mark the second day of the strike.