Birmingham City Council is heading back to court in an appeal over equal pay claims lodged by 4,000 women workers.

But the authority came under fire from trade unions who called for the city to pay up and stop wasting taxpayer’s money in the courts.

The council’s lawyers have drawn up a challenge to April’s Employment Tribunal judgement which awarded equal pay claims worth an estimated £615 million against the city.

The council’s human resources chief Alan Rudge has been advised that “elements of the judgement were incorrect” and the council can reduce its financial cost on appeal.

The dispute centres over a bonus system, scrapped by Coun Rudge in 2008, which unfairly rewarded workers in male dominated manual jobs like road workers, binmen and street sweepers, but were not given to cleaners, dinner ladies and carers, those jobs generally favoured by women.

Coun Rudge said: “There are specific elements of the judgement that are incorrect so I have given notice that we intend to appeal.

“This may not over turn the judgement, but could significantly reduce the financial risk to council.”

He said the council had already settled about 95 per cent of the claims out of court and claimed the unfair pay structure he inherited was dismantled in 2007,

But trade union Unison demanded the authority withdrew the appeal and settled outstanding claims.

West Midland spokesman Tony Rabaiotti said: “Instead of wasting council taxpayer’s valuable money on legal costs, this authority should pay the low paid women employed by the council the money they are owed.

“They’ve wasted millions of pounds in legal fees so far and seem intent on wasting even more.”

Paul Savage, of Action4Equality lawyers, said he had signed up hundreds of fresh claimants since the April judgement.

He said: “We expected an appeal, but challenging a couple of points is not going to overturn a very strong and forthright ruling. The council would be better concentrating on finding the money to settle these claims.”