A portrait of Sir David Attenborough has been unveiled by the Royal Society to mark the broadcaster and naturalist's four decades as a fellow.

In the artwork by Jonathan Yeo, who painted the King's first official portrait since the Coronation, a seated Sir David holds his hands and looks towards the viewer.

Sir David, 98, said: 'It was a tremendous honour to be elected a fellow of the Royal Society over 40 years ago, and that my portrait has now been painted by such a master as Jonathan Yeo for the society's extensive and important collection is extraordinary indeed.

'To spend so much of my life looking at the natural world and attempting to convey to others its amazing complexity, beauty and, increasingly, its fragility, has been a great privilege.

'It has only been possible thanks to the extraordinary natural history filmmakers and the many dedicated scientists who have willingly shared their work with us.'

Sir David and the Royal Society's president Sir Adrian Smith, attended a private unveiling on Tuesday and it was also displayed to the public on BBC's The One Show.

British artist Yeo said: 'It's hard to imagine a public figure who has done more to engage and inspire all generations in the wonders of the natural world than Sir David.

'At a time when too many global leaders are failing to engage seriously in tackling threats to our climate and natural world, Sir David's lifetime of work in communicating and sharing its wonders and importance has been a service to all humanity.

'Sir David has long been a personal inspiration, and so it was a huge honour to be asked to paint his portrait for the Royal Society.

'It has been a thrill as well as a privilege to spend so much time with someone whose wisdom is so deep and broad, and who is also such brilliant and entertaining company.'

Yeo, who has also produced commissions of the late Duke of Edinburgh, the Queen, Sir Tony Blair and Lord Cameron, unveiled the red-coloured painting of the King in May.

His new oil work, which is 130cm x 100cm, celebrates Sir David's career and how he raises awareness of 'climate change and biodiversity'.

Head of library and archives at the Royal Society, Keith Moore, said: 'We're thrilled to have this portrait of Sir David as part of our collections.

'The Royal Society has many pictures of great scientists, over 300 original works of art and around 10,000 engravings and photographs.

'You can find so many individuals from the scientific community of past centuries here: from Isaac Newton to Charles Darwin, and from Albert Einstein and Dorothy Hodgkin.

'But I'd defy you to find anyone who has touched as many people's lives in explaining the ideas behind great science, and how they affect our world, as Sir David Attenborough. He's one of a kind.'

The portrait will be on public display at the Royal Society from July 2 to July 7 as part of the the Summer Science Exhibition.