Sir David Attenborough has paid tribute to Prince Philip's life and legacy.
MORE: Prince Philip's funeral: The most moving photos from the day
The TV icon remembered his friend the Duke of Edinburgh as the coverage of the late royal's funeral began on the BBC on Saturday morning.
Discussing the late royal's life-long appreciation and fascination with the natural world, he said: "He was right there at the beginning at a time when conservation didn't mean much to many people. Even in the 1950s and '60s, he saw it universally."
WATCH: HELLO!'s Emily Nash reports from Prince Philip's funeral
He continued: "The World Wildlife Fund owed a huge amount to his presence. When he spoke about conservation, he spoke about it with passion and knowledge."
The Duke took an early interest in conservation and remained passionate about animals and the environment right up to the end, something to which broadcaster and naturalist Sir David has devoted his own life.
MORE: David Attenborough's beautiful London home revealed
Sir David Attenborough remembered his friend the Duke of Edinburgh
He was an innovator of the environmental movement and lent his support to the World Wide Fund for Nature. In his role as President, HE toured the world, meeting like-minded environmentalists and promoting the cause.
Speaking more generally about the Duke, Sir David added: "He was an extraordinary combination of being formidable and friendly. You knew he was there. He had an amazing presence. It was an extraordinary balancing act between formality and informality."
MORE: Prince Philip enduring passions and hobbies - a look back
The royal spoke of his dedication to environmental causes back in 2012. "If we've got this extraordinary diversity on this globe it seems awfully silly for us to destroy it," he told Fiona Bruce during an interview to mark his 90th birthday.
"All these other creatures have an equal right to exist here, we have no prior rights to the Earth than anybody else and if they're here let's give them a chance to survive."
Prince Philip served as president of World Wide Fund for Nature
MORE: The Queen's secret message to beloved Prince Philip in funeral wreath revealed
Prince Philip's funeral is being broadcast on the BBC, Sky News and ITV, among others today. The ceremony officially began at 3pm with a minute's silence.
In compliance with coronavirus restrictions, there will be no public access. Consequently, the royal family has asked that members of the public do not visit Windsor on the day, but instead watch the funeral from home.
Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.