In a branch consultation covering all relevant regions, 81% voted to reject the offer, giving a major thumbs-down to the suggested 'pay cut' that a below-inflation 2% pay "increase" would represent.

Unison's pay and single status group is now recommending the union proceeds to an industrial action ballot. In tandem with UNISON, the GMB and TGWU-Unite are also preparing to ballot their members on industrial action.

The three unions, who between them represent more than 1 million council workers, registered a formal dispute over pay on 16 July.

Meanwhile, although Unison education workers accepted a staggered 3% offer, the university and colleges union UCU has not yet accepted the deal, and some workplace meetings have rejected it.

UNISON's head of local government, Heather Wakefield, said: "local government workers who provide vital public services are being told all they can expect is a pay cut."

The employers' failure to offer a better deal than the 2% currently on the table was particularly galling in the light of last week's improved offer to NHS staff, Ms Wakefield said.

"Local government staff who work alongside them are the poor relations. Once again, they find themselves at the bottom of the pay heap."

UNISON's NJC committee will meet on 20 August to decide whether to go ahead with a ballot.

Ms Wakefield said negotiations with the LGA and the local government employers were unlikely to restart before then.