The Red Ensign

The Red Ensign, flag of the British merchant fleet, worn by any merchant or private vessel. To be flown from the taffrail at sea in coastal waters, when entering or leaving harbour, and when berthed, so long as you are in commission (i.e. on board and not laid up). When not under way, to be hoisted at 0800 (0900 in winter) and struck at 2100 or sunset, whichever comes first (apparently a custom begun in the days of King Charles to make the flags last longer and therefore reduce the amount of money spent annually by the Navy on replacing worn bunting).