Around 200,000 school staff and council workers across England and Wales are to begin voting on whether to strike over pay.
The ballot of Unison members follows the union’s rejection of a 3.3 per cent pay offer from local government employers.
Unison said the offer fell short of restoring the value of staff pay after years of decline.
Among those being balloted from today are teaching assistants, social workers, waste-collection staff, trading-standards teams, housing officers and librarians.
School support staff pay offer rejected
A teaching assistant will have seen the typical value of their pay fall by around £7,000 since 2010, when measured against Retail Price Index (RPI) inflation, according to Unison.
The government uses a different measure of inflation - the Consumer Price Index (CPI).
RPI is typically higher than official measures of inflation, as a result of different calculation formulas and the inclusion of housing costs.
UK CPI inflation was 2.8 per cent, as of the latest figures covering the year to May. RPI was 3.1 per cent across the same period.
But the Bank of England said in April that UK inflation could peak at 3.6 or 3.7 per cent by the end of this year, and could reach 6 per cent next year in the worst-case scenario.
Teachers were offered a 3.5 per cent pay rise for 2026-27, with the government funding the first 1.7 per cent of the award.
The government said it would fund the first 1.5 per cent of the proposed 3.3 per cent pay award for support staff.
‘Brutal austerity’
The four-week Unison ballot closes on Thursday 6 August. If members back industrial action, walkouts could begin early in the 2026-27 academic year.
The union said low pay was making it harder for councils and schools to recruit and retain staff.
Andrea Egan, general secretary of Unison, said: “Council and school workers kept vital services running through years of brutal austerity, with rising demand and relentless pressure. They deserve far better than another pay offer leaving them falling ever further behind.
“This huge ballot is the direct consequence of employers expecting staff to accept less while delivering more, year after year. That’s taken a growing toll on workers, on local services and on the communities depending on them.”
Ms Egan added: “No one chooses lightly to take strike action, and there’s still time for employers to improve this pay offer and avoid a dispute.
“Failing that, it should come as no surprise if workers decide the only way left to secure the fair pay and respect they deserve is to walk out.”