The union is unhappy with a pay offer of 2% from this April following a pay freeze last year.

TSSA has around 100 members at Balfour working as part of the £1.5bn Central Rail System Alliance contract covering the London North West, London North East and East Midland routes.

Union General Secretary Manuel Cortes, said: “Our brilliant members have shown huge commitment and sacrifice, working through this terrible pandemic, to deliver positive results for Balfour Beatty.

“Now it’s time for the company to step up to the plate with an improved offer – and avoid this looming industrial action.

“No one wants a strike, but we won’t stand by and see our members kicked in the teeth after what has been the hardest year, while company executives trouser huge bonuses.

“As things stand Balfour Beatty’s pay offer is insulting and unacceptable. We are just not having it.”

A Balfour Beatty spokesperson said: “We remain committed to working closely with all parties to reach an appropriate outcome.

“However, as these discussions are ongoing, it would be inappropriate to comment further at this time.”