The Royal Standard of the United Kingdom is flown when the Queen is in residence in one of the royal palaces and on her car, ship or aeroplane. It may be flown on any building, official or private, during a visit by the Queen, if the owner or proprietor so requests. It famously replaces the Union Flag over the Palace of Westminster when the Queen visits during the State Opening of Parliament. The Royal Standard was flown aboard the royal yacht when it was in service and the Queen was on board. The only church that may fly a Royal Standard, even without the presence of the Sovereign, is Westminster Abbey, a Royal Peculiar.
how do you know the queen is home
The Royal Standard of the United Kingdom is flown