The Victoria & Albert Museum has announced that three of its sites will close for two days this week as hundreds of staff prepare to strike.
The charity said it had made the “difficult decision” to close the Young V&A, V&A East and V&A Storehouse on 4 and 5 September.
Its main site in South Kensington will remain open, with this museum’s staff not participating in the strike, but the charity said there “may be individual gallery closures”.
This comes as more than 700 of the V&A’s 1,250-strong workforce are expected to take part in industrial action amid a dispute about pay and working conditions.
Two unions are involved in the negotiations with the museum: The Public and Commercial Services Union has 332 members working at the V&A, while Prospect Union has 400.
Staff at the London satellite sites V&A East, V&A Storehouse and Young V&A will strike on 4 and 5 September, but staff at the main site in South Kensington will remain at work.
Union members across all V&A London sites will also take action short of a strike, including a ban on overtime, work to rule and withdrawal of cooperation.
Staff have demanded 1.5 times pay on bank holidays, an improved pay offer for workers on band six or above and for the V&A to become a Real Living Wage-accredited employer, as well as improved working conditions in extreme heat.
The V&A said its latest pay offer would deliver a bank holiday pay rate increase to 1.5; a “sector-leading” bonus scheme; and a pay rise “well above inflation for all staff”, with an average of just over 4 per cent.
In a statement announcing the closure plans, the V&A said: “Due to planned industrial action, we have made the difficult decision to close V&A East Museum and Storehouse, and Young V&A on the 4 and 5 September. We are very sorry for the inconvenience to our visitors.”
It said the South Kensington site and its Schiaparelli: Fashion Becomes Art exhibit would remain open, but added “there may be individual gallery closures so visitors should check the website before travelling”.
Paula Lamot, national secretary at Prospect Union, said: “The decision to close three V&A sites underlines the point we have been making; our members are critical to the operation of the museum.”
Lamot added the closures could be avoided if the V&A “engage[s] constructively with the trade union position and come[s] up with an offer that our members can accept”.
She also said the union members “will not hesitate to have further strikes” at the main site in Kensington if no such offer is made.
The V&A said: “We deeply regret that the trade unions have voted for strike action.
“We have been negotiating with them in good faith since February and have met the majority of their demands with a significantly improved offer, which we believe is fair, competitive and affordable. We remain available for negotiations with our trade union colleagues.”