Council workers in Barnet, north London, are to strike against privatisation on 13 September.
The Unison members have taken a series of work-to-rule actions since March against the notorious “easyCouncil” plans, also known as “One Barnet”.
Now 400 union members in a dozen departments will walk out on the day their work is set to be handed over to the private sector.
The union has labelled it “Independence Day” to highlight the destruction of local accountability as fat cats get their hands on services.
Branch secretary John Burgess said it will be the first time Barnet Unison members have struck over issues in the council.
“We are going to go out into the community leafleting and then we will be lobbying the councillors as they arrive for the full meeting of the council,” he added.
In February up to 1,000 people marched in Finchley against the privatisation plans before packing into a rally.
The flagship Tory council wants to slash its workforce of 3,500 to a few hundred by outsourcing almost everything, on the model of a budget airline.
It is the “guinea pig” for a programme of mass privatisations the Tories want to roll out across the country.
The union is demanding workers remain directly employed by the council.
Lobby Barnet council: Tuesday 13 September, 5.30pm, Hendon Town Hall