Staff at the world's most famous department store are to be balloted over strike action in a dispute about days off and pay, Unite said.
The union said Harrods boss Mohamed Al Fayed is understood to have told staff, over the Harrods loudspeaker, that they would be given two extra days' leave as a reward for hard work.
Drivers, warehouse operatives, engineers and maintenance workers, who are members of the union, were furious when they found they were excluded from the deal which only applied to shop floor staff. Staff are also angry at the 3.5% pay rise they have been offered.
Unite began balloting 235 essential workers to ask if they want to take strike action. The result is expected on September 3.
Unite regional officer Debbie McSweeney said: "The world's most famous store faces a very expensive strike. Our members keep Harrods running. They ensure the lights stay on, the building operates safely and shoppers can get about the store. It is difficult to imagine how the shop could function properly without them."
Richard Munn, a Unite regional official, said: "It is very worrying that those workers who were not given two extra days holidays are in a recognised union, while the shop floor workers who got the extra leave do not have a recognised union.
"We believe Harrods has many noted customers that will be surprised to learn that the shop treats its workers in this way."
A spokesman for Harrods said: "Whilst industrial action would be inconvenient, it would in no way jeopardise the operation of the store nor the customer experience.
"To succumb to the union's demands would give Unite members greater benefits than those enjoyed by other Harrods' employees.
"Harrods will not be increasing the pay award, nor will it agree to the demand for two further days holiday."
