David Miliband has spoken of his motivation for leaving politics, explaining how the organisation he is joining helped those fleeing the Nazis in the 1930s.
The elder Miliband brother is to join the International Rescue Committee (IRC) in New York which was founded at the suggestion of Albert Einstein.
The Miliband family are Jewish and fled Belgium in 1940 to avoid persecution by the invading Nazis. The father of the political brothers, Ralph Miliband was born in the Flemish country to working class Polish-Jewish immigrants and after serving in the Royal Navy during the Second World War, gained British citizenship and settled in London in 1946.
The IRC responds to the world's worst humanitarian crises and helps people to survive and rebuild their lives. Miliband said in his resignation letter the role would give him the opportunity to help some of the most desperate people in the world.
"The organisation was founded at the suggestion of Albert Einstein in the 1930s for those fleeing the Nazis, so given my own family history there is an additional personal motivation for me," Miliband said in his resignation letter.
"I feel that in doing this job I will be repaying a personal debt. Starting in September, this job brings together my personal story and political life. It represents a new challenge and a new start."
In a release from the IRC, he said: "The IRC’s mission is personal for me because my own parents were refugees who arrived in Britain in the 1940s. I look forward to honouring the memory of those who helped my parents by leading the IRC as it continues to offer help today to uprooted people around the world."
Labour leader Ed Miliband has said that British politics will be "a poorer place" without his brother David, who is stepping down as an MP.
His departure comes two and a half years after the bruising Labour leadership battle which pitted the two brothers against each other and was won by a whisker by Ed on the back of trade union votes.
Younger brother Ed admitted today that the experience had been "difficult", but added: "Time has helped to heal that. I will miss him."