Writing in the book of remembrance, Mr Cameron described Auschwitz as “this place where the darkest chapter of human history happened” and vowed that the world must “never forget”.
During a 90-minute tour of the camp, the Prime Minister saw the train tracks which brought at least 1.1 million men, women and children - the majority of them Jews - to the camp and entered prison huts where they were held and gas chambers where many of them were murdered.
Speaking later, he said his first visit to the camp had filled him with “an overwhelming sense of grief for all those who were killed simply because of their faith, their beliefs or their ethnicity”.
And he said it was “a reminder of why the UK must fight against prejudice, persecution, anti-Semitism and tyranny wherever we find it and stand up for inclusiveness, tolerance and peace”.
The Prime Minister travelled to the notorious site with Mick Davis, the chairman of the Holocaust Commission which he established to ensure Britain has a “permanent and fitting memorial” to the victims of the Nazis.
On a bright, frosty morning, Mr Cameron and Mr Davis were guided around the camp by the director of the Auschwitz-Birkenau State Museum, Piotr Cywinski. The PM bowed his head for a moment’s silence as he placed a candle at the memorial in Birkenau.
In a message in the book of remembrance, the PM said: “Words cannot describe the horror that took place - making it even more important that we never forget. As Elie Wiesel said, failing to remember those who were murdered would be akin to killing them all over again.”