Workers protesting over pay will also organise demos at Crossrail and Newcastle University
Construction workers affiliated to Unite the union are preparing to picket high-profile sites around the country on Wednesday.
Their anger is directed at eight contractors which Unite claims are preparing to cut employees’ pay by 30%.
The firms walked out of wage agreement talks at the end of last year, and the union claims they are attacking workers’ rights by seeking to introduce semi-skilled grades into the mechanical and electrical sectors.
Unite says that five of the eight contractors, Balfour Beatty, Crown House Technologies, Spie Matthew Hall, Shepherd Engineering Services and NG Bailey, have given legal notice of their intention to dismiss thousands of employees before re-engaging them on altered contracts.
Protests will take place at MediaCityUK in Salford, Farringdon Station in London, and the Newcastle University building site in Percy Street, Newcastle.
Each protest will involve around a hundred workers.
Two of the breakaway companies, NG Bailey and Crown House Technologies, are contractors on MediaCityUK, and Crown House also works on Farringdon Station.
One or more of the contractors are said by Unite to be working on the Newcastle University site.
Bill Green, Unite regional officer for the North East, said: “Our members in the Newcastle are furious about this attack by these so-called reputable companies aimed at reducing our members’ income by up to a third.’
“The companies are trying to bulldoze their plans through by ripping long-standing national agreements without any negotiation.’
“These rogue employers should pull back from the brink as their brutal onslaught on workers’ skills, pay, and terms and conditions is causing widespread anger among workers.”