A Privilege day in the United Kingdom is a day of annual leave granted to employees of the Civil Service. These are in addition to bank holidays.
Prior to 2013, there were 2.5 privilege days each year:
Since reforms by the Cabinet Office in 2013, the Maundy Thursday (Easter) and Christmas privilege days are no longer available for new civil servants. For civil servants who were in their positions when the changes came into force, these 1.5 days have been converted into additional annual leave. Because the Queen's Birthday privilege day was granted by the Queen, it would have been difficult for the Cabinet Office to abolish it by an administrative measure, so the Cabinet Office decided to retain this day as a privilege day.
FOI practice
Privilege days still count as "working days" for the purpose of freedom of information requests.