During the Second World War, Ernst worked for the BBC and contributed to two government information films, Night Mail and North Sea. But with evacuation, Ilse and her baby daughter, Eva, left London, settling in Cambridge from 1943-45.
The separation broke up her marriage. After a bitter divorce, Ernst remarried and left in 1948 for Communist East Germany, where he had a successful musical career. He died in 1988.
A single mother, Ilse took her daughter to join the rest of her family in Palestine in 1947. But hostilities at the end of the British mandate and Israel's War of Independence drove them back to England in late 1948. She stayed in London until the last two years of her life.
Although she had embarked on law studies in Berlin, she retrained as a Montessori teacher and taught young children in Montessori schools.
She supplemented her income with translating and interpreting, especially for the Anglo-East German trade mission in London.
In the 1960s and 70s she taught German at evening classes, continuing well past retirement age.
Indomitable and independent till 99, she always retained her belief in the ideals of Communism. She was a member of the Association of Jewish Refugees and joined in its Cambridge meetings when her daughter brought her to live with her in Cambridge.
She is survived by her daughter