Thousands of council workers could go on strike again next month if they are not given a large increase in the London weighting allowance.

The three biggest public sector unions decided at a meeting on Wednesday morning to step up the pressure by threatening a 24-hour strike.

Unions are due to meet employers on 12 September and are warning this will be their last chance to make an offer.

They want a flat rate rise of �4,000 a year to help members meet the costs of living in the capital.

Two strikes

Otherwise workers from refuse collectors to teaching assistants, social workers and street cleaners will be called out on strike.

Unison, which has 55,000 members working in local government in the capital has already held two strikes to demand more money for them.

The Transport and General Workers' Union (TGWU) and the GMB Union have also balloted their members about whether to call for industrial action.

The unions say the current allowance of between �1,400 and �2,600 for most council workers does not bridge the gap between salaries and the high cost of living in the city.

'Expensive'

But a spokesman for the Association of Local Government said councils did not have the extra �250m needed, on top of any national pay settlement, to meet the demands.

A national council workers' strike on 17 July was followed by unions and the Local Government Employers Association agreeing a 10.9% pay increase for the lowest paid workers.

But Jack Dromey, T&G national organiser, said: "Councils in Europe's most expensive capital city have not offered one penny more on London weighting.

"Our members in London have had enough."