The threat of a major council strike rose this weekend, as 1,000 workers from across the country gathered in Birmingham to protest at plans to downgrade thousands of jobs.

Council employees from across the country threw their weight behind colleagues at Birmingham City Council, as they protested against plans to introduce new contracts for the authority's 39,000-strong workforce.

The council wants the new contracts to come into force from April 1, as part of a national review of pay and conditions. It is aimed at ensuring men and women are paid the same, but many workers will have their wages cut as part of the proposals.

Some 14,000 workers could go on strike if the dispute is not resolved.

Peter Allenson, a national officer from Unite, told the rally: "As you know, throughout the UK pay grading reviews are happening but the council here in Birmingham is behaving particularly badly.

"The council has behaved in a diabolical manner and with a group of staff that couldn't be more deserving. It's the biggest employer in local government in this country, yet it has set the worst example of how any employer should behave."

David Robinson, 46, from Kings Norton, is a school caretaker for Birmingham City Council. He will lose £3,000 a year if the proposal is ratified.

"It's terrible," he said. "I will have to leave my job because I cannot afford to take a £3,000 cut in pay. It's a lot of money, isn't it?"

Faye West, 32, a communications officer for the authority, said she would lose £9,000 annually if the proposal went ahead.

She said: "It seems an unfair process because there is no consistency. There are people doing the same job as me who have been regraded differently to me and that is not fair. I have got to worry about how I will pay my mortgage."

Talks over a new equal pay structure have been going on for years, but unions said the council was now planning to impose a new package that would lead to refuse collectors and street cleansers losing half their pay, school meals workers receiving just 1p an hour extra while some managers would have a £2,000 pay rise.

Mary Simpson, 63, from Coventry, said her pay had stayed the same when her employers, Coventry City Council, carried out the same review.

She added: "I am showing solidarity. The sad thing about the whole thing is that councils have been allowed to stagger its implementation so that the effect hasn't been the same as if it had happened all at the same time.

"I believe that had this been implemented (across all councils) at the same time we would have had a national strike."

Tony Rabaiotti, policy manager for the union in the West Midlands, said: "At the end of the day Birmingham is the biggest authority in the country and what happens in Birmingham will be watched by many, many local authorities, not just in the West Midlands but in the rest of the UK."

He added: "We are struggling to talk to them [Birmingham City Council] at the moment. They have said: 'This is it; this is what we are going to do, take it or leave it'.

"They want to put in place a pay scale that doesn't allow people to move up the pay scale - it's got bars and cut-off points at various places."

Gerard Coyne, regional secretary for Unite in the West Midlands, said: "Clearly this is about dealing with inequality but we want that done through a properly-negotiated procedure with a fair grading system. That is not what has happened here."

A council spokesman said: "Staff have the right to legitimately protest but we are disappointed that there is talk of industrial action. This is about righting decades of inequality, underpay and pay discrepancies, principles which I am sure everyone, including the unions, will support.

"In the event of industrial action, the authority will do everything in its power to ensure disruption of services is kept to an absolute minimum. All chief officers have been asked to put in place contingency plans ahead of any possible action occurring."