More than half a million local authority employees in England, Wales and Northern Ireland are staging a two-day walkout on July 16 and 17 after rejecting a 2.45% pay offer.

Mark Serwotka, leader of the Public and Commercial Services union, revealed that up to 100,000 civil servants at a number of Government departments could also take industrial action on one or both of the same days because of long-running disputes over pay.

The Department for Work and Pensions, Transport Department and Home Office are some of the Government departments likely to be involved. The union is in dispute with around 14 departments over pay and jobs and have already held a number of strikes.

The PCS will ballot its entire membership later this year for a fresh round of industrial action but it already has mandates to call strikes in a number of departments.

Mr Serwotka, speaking to thousands of people at the Glastonbury Festival, accused Government ministers of spending too much time talking to millionaires rather than ordinary working people.

"We keep being told to tighten our belts and accept below inflation pay rises but there is nothing left to tighten."

Mr Serwotka urged the Government to listen to low paid workers who were struggling to pay for rising fuel, food and housing costs.

Veteran campaigner Tony Benn also spoke at a rally held in the leftfield area of the festival telling 5,000 people that the amount of money being spent on the wars in Iraq and Afghanistan was "criminal".