Young Holocaust Educational Trust ambassadors played a key role in the charity's dinner at London's Guildhall on Tuesday, stressing their determination to fight against antisemitism and other forms of prejudice.

One of the hosts of the dinner - at which the keynote speaker was Chief Whip Michael Gove - was William Pinder, 19, an HET ambassador for London and a graduate of its Lessons from Auschwitz programme.

He said that when he returned from Auschwitz, he was bombarded with questions from fellow pupils. "I sat down by myself and realised where I had been. It had a really big impact on me.

"The things I saw were so horrific, like the room full of hair and piles of shoes." It had given him "the motivation to try to make sure things like this never happen again".

Co-host Orianne Brown, 19, from Derbyshire, said her involvement in Holocaust education had started with presenting Holocaust Memorial Day assemblies at school.

She had found the Auschwitz visit "numbing". What had really hit home was how the killing was "so planned and systematic. How can human beings build factories to kill one another?" She was concerned by the rise of antisemitism on social media.

" In the past six months I've noticed a lot more offensive comments on Twitter and Facebook. If they were taught about the Holocaust properly, I don't think they would act in the same way."

One of the aims of the dinner, attended by 450 HET supporters, was to consider how next year's 70th anniversary of the liberation of the camps could be commemorated. This might be the last major Shoah-related anniversary to be marked with a "significant number of survivors".

The HET also screened its new appeal film for the first time. It featured testimonies and recollections of survivors read out by their grandchildren, young ambassadors and teachers who have taken part in HET programmes.