The codename for the plans to be put into effect immediately after Queen Elizabeth's death was trending on social media after Buckingham Palace announced the queen was placed under medical supervision out of concern for her health.
Edward Young, Elizabeth's private secretary, will first inform high-ranking government officials of the queen's death, and the message will be communicated across the government using the code phrase " London Bridge is down".
After the royal household releases an official notification to the public about the queen's death, the documents outline how all flags across the London center of British government will be lowered to half mast.
The prime minister will be the first government official to make a public statement and will meet with Charles, the next in line to the throne, before he publicly addresses the nation that evening.
The queen's body will be taken back to London by the royal train and the prime minister and other officials will welcome it.
The queen's funeral is expected to take place 10 days after her death, and in the days leading up to it, Charles plans to visit the UK and Northern Ireland.
Her father, King George VI, the Queen Mother, and her sister Princess Margaret were all laid to rest in the King George VI Memorial Chapel.
The preparations for Elizabeth's death may have been changed since the documents were obtained by Politico. The plans for Elizabeth's death were laid out in a piece published by The Guardian, which went global. According to The Guardian, meetings about the initial London Bridge plans have taken place two or three times a year since 2000. Buckingham Palace used a code named Hyde Park Corner to keep switchboard operators from leaking the news of King George VI's death.
Mobility issues are what we know about the queen's health in recent months.
The doctors are concerned for her health.
There is a plan for when Queen Elizabeth II will die.
There is a plan for the days after the Queen's death.