TAMPA, Fla. (WFLA) — Following the announcement of the queen’s death, a meticulous plan dubbed “Operation London Bridge” sprang into action.

Operation London Bridge, also known by code name “London Bridge Is Down,” is the official plan that will immediately follow the death of Queen Elizabeth II. The plan includes a list of procedures and announcements of her death, the period of official mourning, and the details of her state funeral.

The plans were set up in the 1960s and are updated several times each year, ensuring a smooth transition of the throne to her eldest son, Prince Charles, who will become king if the Queen gives up her throne, retires, or dies.

Immediately following Elizabeth’s death, her private secretary, Sir Christopher Geidt, will be the first official to convey the news, according to The Guardian. Geidt will then contact the prime minister over a secure telephone line using the code phrase “London Bridge.” If the prime minister is not awake, civil servants will say “London Bridge is down.”

From there the news will be communicated to 15 governments outside the UK where the Queen is the head of state and 36 other nations of the Commonwealth.

“For a time, she will be gone without our knowing it,” the Guardian report added. “The information will travel like the compressional wave ahead of an earthquake, detectable only by special equipment.”

When the Queen dies, an announcement will be made to the Press Association and the rest of the world’s media simultaneously.

Simultaneously, a footman in mourning clothes will emerge and pin a dark-edged notice to the gates of Buckingham Palace. While he does this, the palace website will transform into a sombre, single page, showing the same text on a dark background.

In the event Her Majesty dies in Scotland, a separate plan, dubbed “Operation Unicorn” will be followed.

After the queen’s death has been made public, Holyrood Palace, St Giles’ Cathedral, and the Scottish Parliament will serve as the primary points of gathering, as a condolence book open to the public is set up at the latter location.

Parliamentary business will be suspended immediately to allow authorities to prepare for a funeral.

The Queen’s coffin would first lie at Holyrood Palace before it is transported to Waverley station, then taken by the Royal Train to London. If this is not possible, the coffin would be taken by plane to London and welcomed by the prime minister and cabinet ministers.