The crowd outside Buckingham Palace has grown to about 1,000 people.
People outside the gates turned round to take pictures of a rainbow that appeared after a heavy downpour.
Elizabeth II, 96, was the nation’s longest-reigning monarch, serving as head of state for more than 70 years.
The Prince of Wales is now King, having acceded to the throne immediately on the death of his mother.
In a statement, the 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 Queen dedicated her life to her royal duty.
She was the first British monarch in history to reach her Platinum Jubilee, and has died just three months after the national celebrations in June celebrating her 70 years on the throne.
The Queen was also the longest-reigning still-serving monarch in the world.
She mourned the loss of her beloved husband of 73 years, the Duke of Edinburgh, who died aged 99 in April 2021.
A figure of stability in national life, the Queen was head of state, the armed forces, the Commonwealth and the Church of England.
1. A rainbow is seen, as members of the public gather outside Buckingham Palace in central London.
A rainbow is seen, as members of the public gather outside Buckingham Palace in central London. Queen Elizabeth II is under medical supervision with the royal family rushing to be by her side amid serious health fears. Buckingham Palace has issued a statement saying royal doctors were concerned for the Queen's health, as the Prince of Wales and her other children, and the Duke of Cambridge cleared their diaries and immediately headed to her home in the Scottish Highlands. Photo: Victoria Jones
2. Members of the public gather outside Buckingham Palace
The crowd outside Buckingham Palace has grown to about 1,000 people. A helicopter is circling overhead as people wait quietly for any news on the well-being of the Queen. Photo: Yui Mok
3. The gates outside Buckingham Palace
A woman laid the first bouquet at the Queen’s central London residence just after 5pm. Photo: Victoria Jones
4. A rainbow is seen over the Queen Victoria Memorial
A rainbow is seen over the Queen Victoria Memorial as members of the public gather outside Buckingham Palace in central London. Photo: Yui Mok