In 1914, when Merle was 3, Arthur Thompson joined the British Army and later died of pneumonia on the Western Front during the Battle of the Somme. Merle and Charlotte led an impoverished existence in shabby flats in Bombay for a few years. Then, in 1917, they moved to better circumstances in Calcutta (present-day Kolkata). Oberon received a foundation scholarship to attend La Martiniere Calcutta for Girls, one of the best private schools in Calcutta. There, she was constantly taunted for her mixed ethnicity, eventually leading her to quit school and receive lessons at home.