Following the Axis occupation of Greece in the Second World War, he was imprisoned by the Italian authorities. He later fled to the Middle East and joined the predominantly Venizelist government-in-exile based in the Kingdom of Egypt. With British support, King Geórgios II appointed him as Prime Minister, and under his premiership took place the Lebanon conference (May 1944) and later the Caserta Agreement (September 1944), in an attempt to stop the crisis in Greece and the conflicts between EAM and non-EAM forces (a prelude of the civil war) and establish a national unity government.