Holocaust Memorial Day: How daughter of camp survivor forged friendship with SS officer's grandson
They are on opposite sides of one of the most harrowing chapters in history.
But that has not stopped a former GP from Salford, whose parents were Holocaust survivors, forming a remarkable friendship with the grandson of a Nazi war criminal and SS officer.
Noemie Lopain now travels the country with Derek Niemann, a writer and teacher from Sandy in Bedfordshire, telling their family stories of terrible suffering and shame.
It was Noemie who initiated the first meeting, even though the Nazis had tortured and killed members of her family.
Noemie's mother, Renee Bornstein, was just 10 when she was imprisoned by the Gestapo after trying to flee her native France.
She described the terrible screams of those who were tortured and killed, memories which she buried for years, rarely talking about what happened.
Noemie's late father, Ernst, endured seven labour and concentration camps during the war, his own parents and two of his siblings perished in Auschwitz.
During the same period Derek's grandfather, Karl Niemann, had been recruited by the SS as an accountant and administrator.
Rising to the equivalent rank of an SS captain, he organised slave labour in concentration camps such as Auschwitz, Dachau, Buchenwald and Sachsenhausen.
Derek, only learned his chilling family secret a decade ago, after planning a visit to Berlin, to see where his father had grown up, he said he made the 'kind of google search that nobody should make'.
Cross referencing his grandfather's name and address online, he was horrified to read he had volunteered as a Nazi and was part of the extermination of millions of Jews.
'Home of SS-Hauptsturmführer Karl Niemann… crimes against humanity… use of slave labour.'
Derek said: "I was completely shocked. My father always said his father was a pen pusher. It was unbelievable."
He learnt his grandfather was interned in prison camps after the end of the war, and was sent to the denazification commission and charged with war crimes and crimes against humanity.
However, his son Rudi remained openly antisemitic.
"My father had Jewish friends yet made disparaging remarks about 'those Jews'," he said. "That's what he was taught to do and he never broke that conditioning."
Derek says one of his father's memories as a child, was seeing his parents standing at the window looking out at a low building with smoke rising from a chimney.
Rudi's mother said to her husband: "You know what they're doing there? They're burning the Jews. They're killing them, and then burning the bodies."
Derek said his grandmother did not like what the Nazis were doing but she enjoyed the 'lifestyle it gave her'.
He's written a book, A Nazi in the Family: The Hidden Story of an SS Family in Wartime Germany, and wants to play his part in tackling hate.
Noemie's mother Renee is profoundly supportive of her daughter's friendship with Derek, telling her daughter, she wants 'the world to know what people like Karl Niemann are capable of".
"She gave me the approval before she met Derek, they had lunch together, and they became firm friends, everyone who meets Derek loves him."
One of their most recent talks before this year's Holocaust Memorial Day, Derek and Noemie spoke to young footballers at Manchester United and Manchester City.
Noemie said: "Hate against people who are born against Jewish faith in the highest it has ever been, if we forget it will happen again.
"We are seeing a rise in hate on the football terraces, with disturbing chants, we need to challenge this hate and prejudice or it becomes acceptable again."
Derek says the most interesting reaction they get is when they visit a synagogue.
"There are people there, who can't even bare to look at me, when I go in and I can understand that, all the pain, six million dead, caused by people of my blood, having said that, once we have spoken they are the friendliest people, and it is wonderful."
Noemie said: "My father was such a humane man. As a doctor after the war, he treated everyone including Germans.
"He wouldn't allow himself to hate. He said hatred eats up the person who hates."
"Derek and I want to inspire people to have the courage to speak out. And to realise that people can be united even from different backgrounds in a common cause of humanity."
Manchester United invited Noemie and Derek as part of their 'Enrichment Programme' helping to create young role models in the sport.
In May 2022, two Burnley fans were arrested, after making a Nazi salute towards Tottenham supporters during a premier league game.
That is just one of a number of incidents at football grounds, debated in parliament, and lead to calls by MPs for much more to be done to by the football authorities to tackle racism and antisemitism.