Broadcaster Jonathan Dimbleby told the audience at Manchester's Yom Hashoah ceremony that the BBC had not wanted to transmit his father's harrowing report from the Bergen-Belsen concentration camp.
Richard Dimbleby, the BBC's war correspondent, entered the camp just after its liberation in April 1945. When his bosses prevaricated over broadcasting his report, "my father told them he would resign if they did not do so. He wanted to express disgust, horror and outrage over what he saw in Belsen."
The audience of 1,500 - an unprecedented number at the annual event - listened in rapt silence to a clip of the historic report.
Mr Dimbleby added that his father repeatedly broke down in tears while recording his broadcast. And although he never spoke about Belsen to his children, "it became part of his DNA".