The Queen has died at the age of 96, Buckingham Palace has confirmed.
Her Majesty Queen Elizabeth II passed away peacefully at Balmoral after concerns had earlier been raised over her health.
The statement from Buckingham Palace read: "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."
On Thursday afternoon Buckingham Palace issued a rare statement to say the Queen was 'under medical supervision' at her castle in Scotland after doctors became concerned for her health.
Her family travelled to Balmoral to be by her side before the passing was confirmed. Queen Elizabeth II has reigned over the United Kingdom since 1952 and is the country’s longest-serving monarch. Her death marks the end of the Elizabethan era and is certain to trigger an extended period of national mourning.
Prince Charles, her eldest son, now becomes King having held the position of Prince of Wales for the longest period in history. Prince William is now expected to inherit that title. On Tuesday the Queen was pictured in a historic audience with Liz Truss, as she appointed her as the new Prime Minister.
The smiling head of state looked bright but frail and used a walking stick during Tuesday's audience, which followed a visit from outgoing prime minister Boris Johnson as he tendered his resignation. The monarch had ongoing mobility issues and postponed her Privy Council meeting after being advised by royal doctors to "rest" the following day.
The Queen arrived at Aberdeen airport to begin her annual holiday in Scotland on July 21. While at Balmoral she was said to have received family visitors, including the Duke and Duchess of Cambridge and their three children, as well as the Earl and Countess of Wessex and their children, and the Duke of York.
Last week it was announced the Queen would miss the Braemar Gathering in Scotland, the Highland Games event that she traditionally attends during her summer break at Balmoral. As news broke that concerns had been raised over her health on Thursday, The Prince of Wales and Duchess of Cornwall, Prince William, travelled to Balmoral to be by her side.
Despite announcing that the Queen would remain under medical supervision, A Palace spokesperson said she remained 'comfortable and at Balmoral'. Following news of her death, tributes flowed in for the Queen from around the globe from heads of state and political leaders.
As Queen Elizabeth oversaw a period of modernisation and great technological advance in Britain. As well as being sovereign, she was Head of the Commonwealth and key to keeping the bloc of former British Empire territories united.
She was born in Mayfair in 1926 to the Duke and Duchess of York, who later became King George VI and Queen Elizabeth when King Edward VIII abdicated the throne in 1936 to be with his American lover Wallis Simpson.
Elizabeth acceded the throne in 1952 after her father died while she was on a tour of Kenya. As Princess Elizabeth, she married Philip Mountbatten in 1947 before having four children; Charles in 1948, Anne in 1950, Andrew in 1960 and Edward in 1964.
She would later have eight grandchildren; William and Harry, Peter Phillips and Zara Tindall, Princesses Beatrice and Eugenie, and Lady Louise and James, Viscount Severn. She had nine great-grandchildren that form the future of the House of Windsor. George, Charlotte, Louis, Archie, Savannah, Isla, Mia, Lena and Lilibet.
Her first prime minister, Winston Churchill, had just led Britain through the Second World War and became almost a father figure to her. Liz Truss was the 15th prime minister her reign has taken in.
