Today I learned that the flag of the British monarchy, the royal standard, is never put on half-mast because it’s considered the fall of the monarchy itself. Following the famous statement “The king is dead, long live the king!” the king or queen can’t die as long as there is an immediate monarch to step into the position of their predecessor. Means when the king or queen didn’t die, then there is no reason to wear mourning and therefore no reason for half-mast on a state level. Other flags like the Union Jack can and are put on half-mast in case of such an event.
I came across that when watching another old episode of “Wissen macht Ah!” and then looked into the details on Wikipedia. There I also learned that other countries such as Iran or Saudi Arabia also don’t lower their flags to half-mast but for different reasons.