The prime minister has led the tributes to Prince Philip, who has died at the age of 99.
Speaking from Downing Street, Mr Johnson said: “He (Philip) 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.
Live updates from the UK and around the world following the death of Prince Philip
“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.”
I join with the rest of the United Kingdom and the Commonwealth in mourning the loss of His Royal Highness Prince Philip, The Duke of Edinburgh. https://t.co/nLYSBlmnHe pic.twitter.com/RajI33U3tr
Labour leader Sir Keir Starmer, said: “The United Kingdom has lost an extraordinary public servant in Prince Philip.
“Prince Philip dedicated his life to our country – from a distinguished career in the Royal Navy during the Second World War to his decades of service as the Duke of Edinburgh.
“However, he will be remembered most of all for his extraordinary commitment and devotion to The Queen.
“For more than seven decades, he has been at her side. Their marriage has been a symbol of strength, stability and hope, even as the world around them changed – most recently during the pandemic.”
Scotland’s First Minister Nicola Sturgeon tweeted: “I am saddened by news that the Duke of Edinburgh has died.
“I send my personal and deepest condolences – and those of @scotgov and the people of Scotland – to Her Majesty The Queen and her family.”
Scott Morrison, the prime minister of Australia, said in a statement: “Through his service to the Commonwealth he presided as patron or president of nearly 50 organisations in Australia.
“Given his own service, Prince Philip also had a strong connection with the Australian Defence Force.
“For 65 years, The Duke of Edinburgh’s Award scheme has encouraged over 775,000 young Australians to explore their leadership potential.
“Forty thousand young Australians are currently participating in the program.
“Australians send our love and deepest condolences to her Majesty and all the Royal family.”