On one occasion, Powell's yellow skin (he was recovering from jaundice), over-formal dress and strange manner caused him to be mistaken for a Japanese spy. During this period, he declined to meet a Cambridge academic colleague, Glyn Daniel, for a drink or dinner as he was devoting his limited leisure time to studying the poet John Donne. Powell had continued to learn Urdu, consistent with his ambition of becoming Viceroy of India, and when Mountbatten transferred his staff to Kandy, Ceylon, Powell chose to remain in Delhi. He was promoted to full colonel at the end of March 1944, as assistant director of military intelligence in India, giving intelligence support to the Burma campaign of William Slim.