A Statement from Buckingham Palace said:
"It is with deep sorrow that Her Majesty The Queen announces the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh.
His Royal Highness passed away peacefully this morning at Windsor Castle.
Further announcements will made in due course.
The Royal Family join with people around the world in mourning his loss."
Prime Minister, Boris Johnston said:
It was with great sadness that a short time ago I received word from Buckingham Palace that His Royal Highness The Duke of Edinburgh has passed away at the age of 99.
Prince Philip earned the affection of generations here in the United Kingdom, across the Commonwealth and around the world.
He was the longest serving consort in history, one of the last surviving people in this country to have served in the second world war at Cape Matapan, where he was mentioned in despatches for bravery and in the invasion of Sicily, where he saved his ship by his quick thinking and from that conflict he took an ethic of service that he applied throughout the unprecedented changes of the post war era.
Like the expert carriage driver that he was he helped to steer the royal family and the monarchy so that it remains an institution indisputably vital to the balance and happiness of our national life.
He was an environmentalist, and a champion of the natural world long before it was fashionable.
With his Duke of Edinburgh awards scheme he shaped and inspired the lives of countless young people and at literally tens of thousands of events he fostered their hopes and encouraged their ambitions.
We remember the Duke for all of this and above all for his steadfast support for Her Majesty The Queen.
Not just as her consort, by her side every day of her reign, but as her husband, her “strength and stay”, of more than 70 years.
And it is to Her Majesty, and her family, that our nation’s thoughts must turn today.
Because they have lost not just a much-loved and highly respected public figure, but a devoted husband and a proud and loving father, grandfather and, in recent years, great-grandfather.
Speaking on their golden wedding anniversary, Her Majesty said that our country owed her husband “a greater debt than he would ever claim or we shall ever know” and I am sure that estimate is correct.
So we mourn today with Her Majesty The Queen
we offer our condolences to her and to all her family
and we give thanks, as a nation and a Kingdom, for the extraordinary life and work of Prince Philip, Duke of Edinburgh.