Unison said more than 500,000 local government workers in England, Wales and Northern Ireland walked out at the start of a 48-hour stoppage in protest at a 2.45% pay offer.

Employers claimed that 300,000 council workers were on strike, only a quarter of those affected by the dispute.

A snapshot survey of councils by the Local Government Association in all regions of England, Wales and Northern Ireland showed that the North East and North West suffered most disruption to services, while in other parts of the country the industrial action was said to be "sporadic", with most services unaffected.

But Unison said the action was well supported, causing chaos to services ranging from council tax collection to environmental health inspections.

Unison estimated that 11,000 schools closed, along with many libraries, leisure centres. museums, art galleries and theatres, while refuse collections were halted in many parts of the country.

Strikers mounted picket lines outside council buildings and attended lunchtime rallies in many towns and cities.

John Ransford, of the Local Authority Employers, said money was being held by councils as a contingency reserve but it would be "crazy economics" to use it for pay.

Up to 5,000 driving tests could be cancelled because of a separate strike by more than 1,500 members of the Public and Commercial Services Union working for the Driving Standards Agency, the union warned.

The strike begins a week of action over pay by tens of thousands of civil servants in protest at the Government's public sector wage policy.