Queen Elizabeth II, the UK’s longest-serving monarch, has died at Balmoral aged 96, after reigning for 70 years.
Her family gathered at her Scottish estate after concerns grew about her health earlier on Thursday.
The Queen came to the throne in 1952 and witnessed enormous social change.
With her death, her eldest son Charles, the former Prince of Wales, will lead the country in mourning as the new King and head of state for 14 Commonwealth realms.
In a statement, Buckingham Palace said: “The Queen died peacefully at Balmoral this afternoon.
“The King and the Queen Consort will remain at Balmoral this evening and will return to London tomorrow.”
All the Queen’s children travelled to Balmoral, near Aberdeen, after doctors placed the Queen under medical supervision.
Her grandson, Prince William, is also there, with his brother, Prince Harry, on his way.
Prince Charles, 73, heir to the throne since the age of three, is now king, and the Duchess of Cornwall is now Queen Consort.
In a statement, Buckingham Palace said: “The Queen died peacefully at Balmoral this afternoon. The King and the Queen Consort will remain at Balmoral this evening and will return to London tomorrow.”
The royal family’s official website carried the message: “Queen Elizabeth II 1926-2022” along with the official statement issued by Buckingham Palace.
Flags on landmark buildings in Britain were being lowered to half mast as a period of official mourning was announced.
As Queen of the UK and 14 other realms, and head of the 54-nation Commonwealth, Elizabeth II was easily the world’s most recognisable head of state during an extraordinarily long reign.