Schoolchildren and a Holocaust survivor met with the Prime Minister to commemorate Holocaust Memorial Day.
William Pinder and Hannah Hardman, students at St Cecilia's, in Sutherland Grove, Southfields, are ambassadors for the Holocaust Educational Trust (HET).
During the meeting David Cameron signed HET's Book of Commitment, which pledges to preserve the memory of the Holocaust and to challenge prejudice.
Mr Cameron wrote in the book: "Your work is absolutely vital in making sure that we always remember what happened in the Holocaust - and that we never stop learning the lessons.
"We commemorate the lives lost in the Holocaust and think also of those killed more recently in Rwanda, Cambodia, Dafur and Bosnia.
"The tragedy is that so many did suffer from persecution and prejudice, but your work will make sure we never give up this fight and build a better world."
Auschwitz survivor Freda Wineman also witnessed the signing, taking place ahead of Holocaust Memorial Day on January 27.
She said: "It is vital that we mark Holocaust Memorial Day, not only for those like me who were directly affected by it, but to honour and remember the communities destroyed under the Nazis."
William and Hannah were selected to be regional ambassadors for the HET project in 2012 and are tasked with educating their peers about the Holocaust.
The pair have visited Auschwitz-Birkenau, created a hand print memorial to victims and made presentations to their school.