Security guards at Harrods are to take five days of strike action starting later this month in a dispute over pay, unions confirmed.
Last month workers at the Knightsbridge site voted by 97% to walk out, claiming they are being underpaid by being made to attend a separate office 15 minutes before and after their shifts start.
Harrods has previously insisted it pays uniformed security officers "generously" with the cost of the extra work included in pay packets.
But Unite the Union said staff should not go unpaid to attend a separate location before they start work and stay behind after their shift to collect and drop off rotas, keys and DNA spray.
Once every eight weeks the workers are required to attend an unpaid "training day" which also forms part of the dispute, the union added.
The first strike will take place on Saturday February 22 - to ensure maximum disruption on the busiest shopping day of the week at the store - with further walkouts planned for February 26 and 29, followed by March 4 and 7.
Unite received union recognition last year by Harrods management to represent security guards at the store. But talks on pay failed to reach a conclusion.
Staff being forced to work outside of their contracted hours was exposed at Sports Direct's Shirebrook warehouse in recent years.
Workers had to queue through long security posts to leave the warehouse - meaning they were technically earning less than the minimum wage.
It led to a major overhaul of the systems and a public dressing down by politicians for Sports Direct's founder, Mike Ashley.