Education Secretary Nicky Morgan has described her visit to Auschwitz-Birkenau as "truly life-changing" in shaping her thinking about the Holocaust.
Mrs Morgan - who made the trip in 2012 with students from her Loughborough constituency - was speaking before the Holocaust Educational Trust's Lord Merlyn-Rees memorial lecture at the Houses of Parliament on Tuesday.
She went on to tell her audience of 200, including fellow MPs and survivors, that "there is a before-the-visit life and an after-the-visit life, where you look at the world in a different way. Once you've visited Auschwitz, it never leaves you."
Although praising the HET's work, she warned there was "no room for complacency" in Shoah education for children, who were in the "front line" of the battle against intolerance.
"I can't stress how important it is that every generation of young people not only understands what happened at Auschwitz and other camps, but also understands the horror of what happened, so that the next generation can be steadfast in never letting it happen again. The Holocaust did not begin in the gas chambers. It began with hateful, ignorant, dangerous views."
Guests also heard from Eva Clarke, 70, who was born at the gates of Austrian concentration camp Mauthausen days before it was liberated. Mrs Clarke said her mother, Anka Bergman, called Auschwitz - where she spent 10 days - "Dante's Inferno".
Anka Bergman was initially told that she had given birth to a boy. "I was named Martin, and she held me all through the night.
"In the morning, someone said: 'Would you like me to wash your baby?' The person brought me back and said: 'Here's your baby girl.'
"My mother was in hysterics wondering what had happened to me. But when she calmed down she was pleased, because she had wanted a baby girl."
Mrs Clarke - who speaks to school groups on behalf of the HET - added that her mother had gradually opened up to her about life during the Shoah.
"From a very young age, she started to tell me tiny snippets of her wartime experiences as she felt that I was able to cope with the details."
She was "six or seven" when her mother told her that her husband, Karel Bergman, was not Eva's father. Her biological dad, Bernd Nathan, was killed at Auschwitz.
"I must've been a rather precocious little brat," Mrs Clarke said. "She heard me go downstairs to play with someone in the garden and say: 'I've got two daddies and you've only got one.' She said that was when she knew it wouldn't hurt me."
Mrs Clarke has collaborated with author Wendy Holden on a book, Born Survivors, on those born in death camps. "At the end of our first meeting I asked if she'd do me the honour of letting me write her story," Ms Holden recalled. "She reached out, touched my arm and said: 'I've been waiting for you for 68 years.'"