Their next strike is scheduled for 30 November to coincide with public sector trade unions’ day of action against the government’s proposed changes to pensions.
Barnet Council announced its intention to outsource its entire portfolio of built environment functions as part of a major reform of service delivery earlier this year.
A tender document, released in June, gave notice of the local authority's plans to contract out a host of services including regeneration, strategic planning, housing strategy, highways and transport, building control and structures, planning development management, land charges, environmental health and architectural services.
Adam Driscoll, Unison representative for Barnet’s planning strategy and regeneration staff, said he organised the vigil outside a planning committee meeting, "to raise awareness among members about the legal advice that is starting to come out that they cannot outsource decision making in planning".
Driscoll said the strikes were being held to protest "against the principle of changing the identity of our employer".
While job losses have not been spelled out, Barnet is seeking 10 per cent efficiency savings from the deal, he said.
Council deputy leader Daniel Thomas called the strikes "disappointing".
He said: "We have made a very generous offer in terms of protecting membership of the local government pension scheme.
"Staff would remain in the scheme and this strike is about the name on the bottom of a pay slip and which employer contributes to that pension. I’m sure that’s a level of certainty a lot of Barnet residents would envy."