Oxfordshire could be “brought to a halt” by the biggest wave of industrial action since the 1926 General Strike, unions have warned.

The UK’s two largest trade unions, Unite and Unison, joined the Fire Brigades’ Union (FBU) in announcing strike ballots over planned changes to their pensions.

With nine other unions already threatening action, up to three million teachers, nurses, local authority workers, civil servants and police officers could walk out on Wednesday, November 30.

At the Trades Union Congress London conference, union leaders warned of a “long, hard and dirty” campaign stretching through the winter and into 2012.

Gawain Little, president of the Oxford and District Trades Union Council, said strikes could bring down the Government.

He added: “What we seem to be seeing now is effectively the coordination of a General Strike across the public sector.

“In Oxfordshire, we have more than the average number of public sector workers than in the rest of the country, and if they take strike action, it would bring Oxfordshire to a halt for a day.”

Mr Little said he would like to see the dispute resolved without strike action.

He added: “We want Government to recognise our pension rights and our terms and conditions, and to step back from the assault on public services and public service workers.

“If they are unwilling to change policy, we will want a change of Government.”

Since firefighters last went on strike in 2003, Green Goddess fire engines used by the Army to provide emergency cover have been retired.

FBU Oxfordshire’s membership secretary Rachel Dobson said strike action was a last resort, but pension funds were being raided to pay off the national deficit.

Some 3,500 health workers will be balloted by Unison Oxfordshre Health.Secretary Ian Mckendrick, a John Radcliffe Hospital nurse, said members were shocked and angry at plans to make them work longer and pay more into their pensions, but receive a smaller retirement package.

GMB national officer Brian Strutton told the London conference the dispute would involve hospital and ambulance workers, binmen and cemetery workers.

Oxford East MP Andrew Smith said: “Union members need to think through very carefully what they might achieve through strike action and whether they would get public support.”