In the early war years, he contributed articles on military strategy to the Evening Standard and, on the recommendation of Michael Foot, was hired by Aneurin Bevan in 1942 as the de facto editor of the left-wing weekly Tribune.
(Bevan was nominally the editor but had neither the time nor the technical expertise to do the job, and Kimche was both an alien and a member of the ILP rather than the Labour Party, which Tribune supported.)
He left Tribune to join Reuters in 1945 but returned in 1946, though by now his primary interest was in the Middle East—specifically, in the creation of a Jewish state in Palestine.
He was fired from his Tribune job after disappearing from the office in December 1947 to Istanbul to negotiate safe passage with the Turkish authorities for two ships sailing from Bulgaria with thousands of Jews aboard bound for Palestine.
Kimche documents this group's activities in arranging for Jewish orphans to arrive from all over Europe to Marseilles in 1947 and board the Exodus, which was bound for Palestine.