Sir Andrew joined the Bank in 1966 to work first in the Economics Department and then in the Cashier's Department. In 1972 he was seconded to the International Monetary Fund to become Personal Assistant to the Managing Director. He subsequently resigned from the Bank to join the Fund's staff. He was Chief of the Special Studies Division from 1974-77, working on the reform of the International Monetary System, before moving to the Middle Eastern department where he conducted negotiations with Egypt and Pakistan on IMF programmes. In 1982 he was appointed Deputy Director of the IMF Research Department.