IT was the day when unions claimed Britain saw "the biggest strike in a generation" with up to two million public sector workers taking to the streets.

Yet Prime Minister David Cameron dismissed yesterday's industrial action as "a damp squib" with Downing Street insisting the turnout was much lower than union estimates and disruption not as great as feared.

As trade union chiefs boasted of a "historic" turnout, Conservative sources suggested many workers had used the day of action to do their Christmas shopping.

Last night, Francis Maude, the Cabinet Office Minister, thanked the "committed public sector workers who turned up to work and delivered essential services. Nurses, teachers, job centre staff and many others came in as usual to keep the country running and we are very grateful for their dedication".

Earlier, Brendan Barber, general secretary of the TUC, said there had been huge support for the action against the proposed changes to public sector pensions. Up to 90% of some organisations had taken part, often for the first time.

"They have acted in a dignified way and got their voice across loud and clear," declared Mr Barber.

An estimated 300,000 workers went on strike in Scotland and, in some respects, the industrial action was greater north of the Border than south of it. While virtually all schools in Scotland were closed, the figure for England was 62%. Consequently, many parents were forced to take a day off work or arrange alternative childcare.

There were more than 1000 rallies throughout the UK with several mass demonstrations across Scotland, including in Glasgow and Edinburgh.

Picket lines were set up outside hospitals, schools and recreational facilities around the country.

Thousands of Scottish patients had hospital appointments and operations cancelled or postponed as around 50,000 healthcare staff took part in the strike. However, urgent operations went ahead and emergency services continued to work normally.

However, in London the stretched ambulance service was dealing only with "critical" incidents, with police drafted in for less urgent cases and to transport medical staff if needed.

At Holyrood, Labour and Green MSPs opted to miss a Scottish Government debate on the pensions reforms, choosing instead to join the strikers.

Mike Kirby, president of the STUC, said it had been remarkable that almost 30 trade unions had acted together, probably for the first time in their histories. He added: "Even at this stage we hope the Government will realise they need to get back down to some serious discussion."

At Westminster, Mr Cameron clashed in heated exchanges with Ed Miliband, accusing him of being "irresponsible, left-wing and weak" for backing the strike. The Labour leader hit back, making clear he was not going to "demonise" ordinary workers and said the industrial action was down to "the Government's failure" to seal a deal with the unions.

The Prime Minister branded the industrial action "irresponsible and damaging" and told MPs support among public sector workers had been far from universal.

At question time in the Commons, he said: "So far the evidence would suggest that around 40% of schools are open and less than a third of the civil service is actually striking.

"On our borders the signs are the contingency measures are minimising the impact. We have full cover in terms of ambulance services and only 18 out of 900 job centres have closed.

"Despite the disappointment of the party opposite, that support irresponsible and damaging strikes, it looks like something of a damp squib."

Elsewhere, the Institute for Fiscal Studies number-crunched the Chancellor's autumn statement and said Britain was looking at a "lost decade".

Austerity measures and economic stagnation would wipe £2500 off families' incomes in just three years. By the time of the 2015 General Election, the squeeze will have wound back more than a decade of rising wealth, added the IFS.