After a recent announcement that guest services would be outsourced to a private company, employees of the National Gallery voted to strike from February 3rd to the 7th. The workers, who are represented by the Public and Commercial Services (PCS), voted nine to one to take industrial action. The gallery has maintained that these changes will not lead to any job losses.
See "National Gallery Staff to Stage Five-Day Walk-Out", BBC News Online, January 27, 2015