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 Prince of Wales is now King, having acceded to the throne immediately on the death of his mother.
Taoiseach Micheal Martin said in a statement: “On behalf of the Government of Ireland, I would like to convey my deepest sympathy to His Majesty King Charles, the Royal Family, the UK Government and the British people on the loss of their beloved monarch, Her Majesty Queen Elizabeth.
Our world is a poorer place for her passing but a far richer and better place as a result of her long life and enduring contribution
Taoiseach Micheal Martin
“The Queen’s reign was one of historic duration, immense consequence and a focus of respect and admiration around the world. Her dedication to duty and public service were self-evident and her wisdom and experience truly unique.”
He said the Queen’s passing was “the end of an era”.
“To her grieving family and people, the Irish Government join with you in mourning the loss of an exceptional woman who led by quiet and dignified example and who touched so many lives over her exceptionally long reign.
“Our world is a poorer place for her passing but a far richer and better place as a result of her long life and enduring contribution.”
In a statement, President Higgins expressed his “profound regret and a deep personal sadness” at the death of the Queen.
“On behalf of the people of Ireland, may I express my heartfelt sympathy to His Majesty King Charles and to the Royal Family on their very great personal loss.
“May I offer my deepest condolences to the British people and to the members of the Commonwealth on the loss of a unique, committed and deeply respected Head of State.”
Mr Higgins continued: “Her Majesty served the British people with exceptional dignity. Her personal commitment to her role and extraordinary sense of duty were the hallmarks of her period as Queen, which will hold a unique place in British history.
“Her reign of 70 years encompassed periods of enormous change, during which she represented a remarkable source of reassurance to the British people.
“This was a reassurance based on a realism of the significance of present events, rather than any narrow conception of history.
“This was so well-reflected by a remarkable generosity of spirit which helped to foster a more inclusive relationship both with the British people themselves and with those with whom her country has experienced a complex, and often difficult, history.”
“As we offer our condolences to all our neighbours in the United Kingdom, following the loss of a remarkable friend of Ireland, we remember the role Queen Elizabeth played in celebrating the warm and enduring friendship, and her great impact on the bonds of mutual understanding, between our two peoples.
“She will be deeply missed.”