Staff at the world-famous Royal Opera House in Covent Garden are set to vote on staging strike action over pay.
The Broadcasting, Entertainment, Cinematograph and Theatre Union (Bectu), which represents all staff at the venue except musicians and performers, said it would serve formal notice of a strike ballot later this week.
It comes after talks aimed at resolving the pay row ended without agreement.
The union wants its members to receive a four per cent increase over 12 months but said management was only prepared to offer the same rise over 18 months.
Supervisory official Willy Donaghy said: “It’s disappointing to have to say that we were the only side which came prepared to negotiate.
"Management’s last offer today was worse than the one previously tabled and rejected by our members."
The Royal Opera House's chief executive Alex Beard wrote to staff saying a "fair" pay offer worth four per cent had been made, backdated to last month.
He said he was disappointed that agreement could not be made, adding that the ROH was keen to implement a pay rise as soon as possible.
The ballot is expected to begin within the next fortnight.
Additional reporting by PA
