In a statement shortly after midday, the palace said: "His Royal Highness passed away peacefully this morning at Windsor Castle."
The duke, who was the longest-serving consort in British history, had returned to Windsor Castle on 16 March after spending a month in hospital.
Boris Johnson said he "inspired the lives of countless young people".
The palace added: "The Royal Family join with people around the world in mourning his loss."
Speaking at Downing Street, the prime minister said he received the news of the duke's death "with great sadness".
"Prince Philip earned the affection of generations here in the United Kingdom, across the Commonwealth, and around the world," he said.
The flag at Buckingham Palace was lowered to half-mast and a notice was posted on the gates following the announcement of the duke's death.
https://www.bbc.com/news/uk-11...