Beefeaters at the Tower of London have gone on strike in a row over pensions.
It is the first time that the iconic guardians of the Tower London have been on strike since 1963.
Jewel house wardens and members of staff at other historical palaces are also taking part in industrial action.
Those involved are angry that their pensions have been changed from a final salary model to what the GMB union described as an “inferior” version.
The trade union said 91% of its members voted in favour of strike action, on a turnout of 88%, and accused Historical Royal Palaces of “engaging in a race to the bottom”.
John Barnes, chief executive of Historic Royal Palaces, told Forces News that all sites would remain open and he did not expect the strike to have an impact on day to day operations:
"Although we fully respect the rights of trade union members to take industrial action, the announcement is disappointing.
"However, it will not change our decision to close the Defined Benefit scheme.
"We have already offered substantial compensation and transition arrangements to the 11% of our staff who are affected during a lengthy consultation. The benefits they have already accrued will be fully protected, and they will be transferred onto the same competitive Defined Contribution scheme as the other 89% of their colleagues in April 2019.
"The closure of the scheme enables us to increase employer contributions to pensions for everyone by 2% - an offer that is fundamentally fairer to our entire workforce. "
Yeoman Warders, more commonly known as 'beefeaters', are trusted to safeguard the crown jewels.
While in the past they used to look after inmates locked up in the tower, nowadays they mainly act as tour guides when not performing ceremonial duties.
The Yeomen Warders and their families live in tied accommodation inside the fortress, paying council taxes and a portion of their salaries for rent.