Tony Blair has said Holocaust Memorial Day is a reminder of the need to tackle racism and intolerance head on.
Tony Blair says the testimony of those involved must not die
Events marking the millions of victims of the World War II Nazi concentration camps are taking place across the UK.
The prime minister said the Holocaust was a "uniquely terrible" event and it did not bring to an end intolerance, hatred and genocide.
About 25,000 people are set to attend 600 events, including the main memorial in Newcastle-upon-Tyne on Sunday.
Mr Blair said: "The Holocaust was a uniquely terrible event in human history. We are the last generation who will be able to hear directly from its survivors and liberators. We must ensure their testimony does not die.
"We must remember, too, those individuals who stood out against this tide of evil, who risked everything in the name of humanity.
"We must reflect as well that intolerance, hatred, even genocide, did not end 60 years ago.
The prime minister added: "Holocaust Memorial Day underlines both our duty to remember the horrors of the past and the responsibility of each of us to shape the future so they are never repeated."
Communities Secretary Ruth Kelly, Chief Rabbi Sir Jonathon Sacks and actor Henry Goodman will attend the event at the Theatre Royal in Newcastle.
Holocaust Memorial Day Trust chief executive Nick Joseph said the commemoration would provide a focus to remember the victims of the Holocaust and understand the lessons that can be learned.
Other major events will take place at locations including Leeds Town Hall, Birmingham's Centenary Square and Catford Synagogue in London.
The memorial day, which was established in 1999 and is also being commemorated around the world, marks the liberation of the Auschwitz-Birkenau concentration camp.