Union leaders have said they may call council workers out on strike after accusing local authority bosses of introducing a time limit on elements of a pay deal.

Officials at Unison, along with Unite and the GMB, hit out at Cosla, which represents all 32 councils in Scotland, over parts of an agreement tabled at the start of last month.

The unions say proposals for an extra day’s leave and the payment of social worker registration fees has been limited to one year, rather than perpetuity.

Union members previously voted to accept the pay offer but officials say their mandate from an earlier ballot for strike action remains live.

Strikes took place at a number of local authorities, including East Renfrewshire Council, this summer, with garbage left to pile up in the streets.

However, these were suspended at the end of September.

Johanna Baxter, Unison Scotland’s head of local government, accused Cosla of “appalling behaviour” over elements of the pay deal.

She said: “Either the employer did not even understand the offer they themselves were making or they did and are now trying to renege on it before it’s even been implemented.

“Either way it will be our members that suffer if they are allowed to get away with it.

“We have made clear to the employer and the Scottish Government that our strike mandates remain live and all three trade unions are under increasing pressure from members, who are rapidly losing faith in their employer, to lift the strike suspensions and call members out if a resolution is not achieved quickly.

“Our members will rightly be questioning the value of Cosla if they cannot be trusted to draft an offer that they understand or uphold one that they do understand.”

However, a spokesman for Cosla defended its actions.

He said: “We value our local government workforce highly. That is why, in an attempt to get the money to the local government workforce as soon as possible, we have offered to separate the pay element of the agreement from the parts that require clarification.

“On the clarification points, in the interests of Cosla’s members, and given significant financial constraints across the public sector, we are working with the Scottish Government to ensure there is a shared understanding in relation to all parts of the deal.”