At 10pm one recent Sunday evening, Sir David Attenborough received a knock at the door of his Richmond home. It was a concerned neighbour who had just read on Twitter that the veteran broadcaster was dead.
"My daughter answered the door and the neighbour asked if it was true," the 93-year-old recounts with a devilish twinkle in his eye. "She said: 'Wait there and I'll go and ask him.' I was watching the news on television."
