It tolls when a member of the Royal Family dies and was heard after the deaths of Diana, Princess of Wales, His Royal Highness The Prince Philip, Duke of Edinburgh, and Queen Elizabeth The Queen Mother. It is now rung for ceremonial purposes to commemorate disasters such as the &lt;a href="September%2011%20attacks"&gt;9/11&lt;/a&gt; disaster, the Asian tsunami, and the London Bombings, and is always rung at the start and end of the two minutes silence on Armistice Day.