On the outbreak of World War II Deutscher moved to England and began writing for The Observer. He also became chief European correspondent for The Economist. Deutscher wrote several books about the Soviet Union including Stalin (1949), Soviet Trade Unions (1950), Russia after Stalin (1953), Trotsky: The Prophet Armed (1954), Heretics and Renegades (1955), Trotsky: The Prophet Unarmed (1959), The Great Contest (1960), Trotsky: The Prophet Outcast (1963) and Ironies of History, Essays on Contemporary Communism (1966).
Deutscher died in London in 1967.