Hellmann was a member of the Social Democratic youth movement and SPD Reichstag parliamentary group. He had to flee Nazi-Germany due to his underground activities in 1935. He and his wife Eva Hellmann eventually emigrated from Prague to England in the late 1930s.

Henry Hellmann (formerly known as Heinrich Jakubowicz, 1906-1984) was born in Breslau but grew up in Berlin. He was in the Social Democratic youth movement (SAJ) and in the SPD from 1925. Between 1930 and 1933 he was a member of the SPD Reichstag parliamentary group. Heinrich Jakubowicz was present at the\"Vorwärt\" siege and the arrest of the SPD executive by the SA. Due to his activities in the underground group\"Neu Beginne\" he had to emigrate in 1935. Jakubowicz fled to Czechoslovakia, where he got married to Eva Hellmann (1907-1986), a teacher from Prague. He soon emigrated to England followed by his wife shortly after. They were reunited again in 1939. Several of Eva and Henry Hellmann's family and friends perished in concentration camps. Eva's mother and her eldest brother with his wife and children were deported to Auschwitz. Only her brother survived Auschwitz.

Henry worked as a translator and journalist in the UK. He changed his name to Henry Hellmann when he was naturalised in 1947. The couple's daughter, Anna Maria Ruth, was born in 1943.