Proclamation of accession of Elizabeth II
Elizabeth II was proclaimed Queen of the United Kingdom and other Commonwealth realms after her father, King George VI, died in the early hours of 6 February 1952, while Elizabeth was in Kenya. Proclamations were made in different Commonwealth realms on 6, 7, 8, and 11 February (depending on geographic location and time zone).
Source: Wikipedia — Proclamation of accession of Elizabeth II (CC BY-SA 4.0)