Elsewhere on Tuesday, Unison, one of the UK’s largest unions, set the scene for more NHS strikes. In a consultation, it asked health worker members in England and Wales whether they would be prepared to walk out if their pay “fails to keep up with rising living costs”.

It comes as Angela Rayner’s workers’ rights reforms faces scrutiny in the House of Lords.

The plans, which could come into force later this year, will expand workers’ right to strike further.

Andrew Griffith, the shadow business secretary, said ministers were “reaping what they sow”, telling The Telegraph: “With the £31 million in union donations since Starmer became leader, and private political summits with union bosses in No 10, it’s no wonder the trade unions think they’ve got the upper hand.”

The new threats from the NEU and Unison come after Unite, the union behind the Birmingham bin crisis, warned that the chaos in England’s second city could “absolutely” spread to the rest of the country.

Sharon Graham, the union’s leader, said on Tuesday she would give the green light for action in “other areas” if councils targeted low-paid workers.

Tensions between the unions and Labour had cooled last year after the public sector pay rises. Ms Reeves has since proposed a 2.8 per cent pay rise for teachers, medics and civil servants for 2025-26, insisting that was all ministers could afford against a “challenging financial backdrop”.

The offer met a backlash from unions last year, with doctors and nurses warning of further industrial action.