Tributes have poured in from the worlds of entertainment and politics following the death of Richard Attenborough.
The Oscar-winning actor and director died on Sunday at the age of 90.
Steven Spielberg said he was "in an endless line of those who completely adored him". David Puttnam called him "completely irreplaceable".
Prime Minister David Cameron said he was "one of the greats of cinema", while Ed Miliband called it "a sad day" for film "and the Labour movement".
Lord Attenborough was a member of the Labour party for many years, and much of his work - such as Cry Freedom and Gandhi - reflected his liberal political beliefs.
Sarah Brown, wife of former prime minister Gordon Brown, tweeted that he was a "true gent w/a [with a] social conscience".
Tony Blair said the filmmaker had "an absolute passion for human dignity and the equality of all".
"As a supporter of progressive causes from the anti-apartheid movement to the celebration of India's independence, he was way ahead of his time," he said.
Speaking to BBC Radio 4's Today programme, friend and fellow filmmaker Lord Puttnam paid tribute not just to the talent Lord Attenborough brought to the screen, but to his tireless work as a public figure.
"This is a most remarkable man who, when you string together the things he did, the things he helped, the things he salvaged, it's mind-boggling the list of decent, good things he did for Britain."
Lord Attenborough's entry in Who's Who listed more than 30 organisations of which he was or had been a director, trustee, fellow, chairman or president, including the British Film Institute, the Tate Gallery and the Muscular Dystrophy Group.
Chelsea Football Club was another of his enduring passions. In a statement the club said: "Lord Attenborough was a thoroughly lovely and talented man who used his fame and influence for the good of the many causes close to his heart. We will always be grateful that our football club was one of them."
Former TV executive Michael Grade said: "Dickie was essentially a man who put much more in than he ever took out of the industry."
Sir Ben Kingsley, who played the title role in Lord Attenborough's Oscar-winning epic Gandhi, said the filmmaker gave him the role "with great grace and joy".
"I along with millions of others whom he touched through his life and work will miss him dearly."
Co-stars from across the Atlantic also paid tribute, remembering the British star with great fondness.
Mia Farrow, with whom he starred in the Guns at Batasi, called him "the kindest man I have ever had the privilege of working with. A Prince".
Mara Wilson, with whom he starred as Father Christmas in A Miracle on 34th Street, said he was "the only Santa Claus I ever believed in. A wonderful man".
"He will always be my Kris Kringle," tweeted fellow 34th Street star, Elizabeth Perkins.
Figures from the world of British comedy also praised the man who Melvyn Bragg said "on the surface appeared very jolly... but was a serious man, extremely concerned about making the world a better place".
Ricky Gervais called him "one of the true greats of silver screen". Little Britain star David Walliams wrote: "Richard Attenborough as Pinkie in Brighton Rock from 1947. One of the greatest film performances of all time."
Stephen Fry took to Twitter to pay his respects saying he did "so, so much in so many arenas". Sir Roger Moore hailed him as "a wonderful and talented man".
The British Academy of Film and Television Awards (Bafta) said in a statement: "We are deeply saddened by the death of Lord Attenborough Kt CBE, a monumental figure in Bafta's history.
"Lord Attenborough was intimately involved with the Academy for over 50 years. He believed in it passionately, supported it tirelessly and was integral to the organisation that Bafta has become today."
Lord Attenborough was a trustee of Bafta from 1972 to 2003, and proposed the introduction of an Academy Fellowship, which he himself received in 1983.
As an actor and director, he won three Baftas, two for Gandhi - again in 1983 - and a third for his performance in two films, Guns at Batasi and Seance on a Wet Afternoon, in 1963.
Speaking of his contribution to British film, Lord Bragg told the BBC "nobody has done as much as he has for one industry".
The filmmaker had been frail for some time, having moved into a nursing home to be with his wife of nearly 60 years, actress Sheila Sim, last year.
His son Michael - a theatre director - revealed the news of his death to the BBC on Sunday evening. The couple also had two daughters, actress Charlotte, and Jane, who died tragically in the Asian tsunami in 2004.