A broadcast of Richard Dimbleby’s wartime report on the Bergen-Belsen concentration camp was a chilling reminder of the horrors of genocide to the 1,000 guests at today's national Holocaust Memorial Day ceremony in Westminster.

Dimbleby spoke of thousands of prisoners “dying every hour, every minute”, and the sight of “bony emaciated faces”.

Mr Dimbleby’s son Jonathan delivered the keynote address to survivors and their families gathered at the Queen Elizabeth II Centre, describing the profound impact the transmission had on his family.

“Most citizens hearing his voice over the wires were in ignorance. But his report was very nearly not broadcast at all. The BBC’s immediate response was that it could not be true, that he was exaggerating. They wanted someone to corroborate the story.

“My father was incandescent. He told them that if they did not transmit that broadcast he would never broadcast again.

“[The broadcast] is irrefutable evidence of the Holocaust. Evidence that remains of ever-great importance.

“Antisemitism is a poison yet to be eliminated. In some, too many parts of the world, it is resurgent. Even in the very countries of central and eastern Europe that the Nazis committed their atrocities.

“My father’s life was marked by a reverence for those values which were seared into him by what he saw in Bergen-Belsen – justice, tolerance and freedom.”

But there was controversy as Mr Dimbleby used his speech to warn against confusing “antisemitism with the right to criticise - even strongly - the policies of the Jewish state to the same degree as one might any other democracy”. 

Earlier the Chief Rabbi praised the “achievements of the Jewish state” since the Holocaust, saying that European would have “gone differently” had it existed in the 1930s and ‘40s. 

Polish-born Helen Aronson, 90, who survived the Lodz ghetto, spoke emotionally about the loss of her father during the Shoah, ending her speech by appealing to her audience to show “tolerance, and to seek out tyrants whose aim is to kill for no reason at all”.

Labour leader Jeremy Corbyn was also present, along with London Mayor Sadiq Khan and Communities Secretary Sajid Javid. Guests were also urged to remember victims of genocides in Cambodia, Bosnia, Rwanda and Darfur. Olivia Marks-Woldman, the HMD Trust chief executive, used her address to draw attention to the ongoing humanitarian crisis in Myanmar.

Some 8,000 HMD events are taking place across the UK this week.