UNIONS hailed the strike by up to 2m public sector workers as “historic” as they angrily rejected claims by the Prime Minister that the biggest walkout in a generation had been a “damp squib”.

David Cameron told the Commons that the “irresponsible and damaging” industrial action had been “far from universally supported” as he defended the Government’s controversial pension reforms.

Officials from 30 unions involved in yesterday’s strike reported huge support, with up to 90% taking action.

The strike closed more than three quarters of schools in England, as well as courts, museums, libraries and jobcentres, disrupted transport, hospitals and Government departments, led to around 15% of driving tests being cancelled, and was described by unions as the biggest since the 1979 Winter of Discontent.

Physiotherapists, headteachers, librarians, lollipop ladies, refuse collectors, weather forecasters and scientists were among those involved.

Civil service union Prospect said action by 26,000 of its members alone disrupted or stopped work at more than 400 locations, ranging from defence sites to prisons.

More than 1,000 rallies were held across the UK, including in central London attended by tens of thousands of workers, some with their children.

Liverpool-born Len McCluskey, leader of Unite, said the rally showed the depth of anger among workers, adding: “The Prime Minister is completely out of touch. There has been a fantastic response both from workers and the general public. The Government can try to spin and tell lies, but they have been found out.”

University and College Union leader Sally Hunt said: “Cheap pot-shots add nothing to what should be a serious debate about millions of people’s futures, and just expose how out of touch the Prime Minister really is.”

Warnings of massive delays at Heathrow airport failed to materialise, with passengers saying border controls were “better than usual”.

Union officials accused the Government of “ramping up” possible airport disruption.

The Public and Commercial Services union reported a “huge” turn-out for the strike, with up to 90% of staff in some Government departments taking action.

Unison leader Dave Prentis said: “I wouldn’t call 2m taking strike action a damp squib.”

Cabinet Office minister Francis Maude said the strike was “inappropriate, untimely and irresponsible”, and added: “Claims there are no negotiations going on are simply not true.”