How do you know if the Queen is at home? Look at the flag flying from the roof, the Royal Standard is white with the family crest in the centre and surrounded by the four state crests. They only fly the Union Jack when she is away. From 26 July until 24 September the general public is allowed to view 19 of the 654 rooms inside and part of the garden. There are around 6000 visitors a day during this period so the visits are timed in 15min intervals between 9.45am and 3.45pm. Tickets can be bought online or from the ticket office in Green Park. Changing of the Guard, daily 11.30am Apr-Jul, alternate days Aug-Mar.