The release of the Turkish detainees in Malta was accomplished in exchange for 22 British prisoners held by Mustafa Kemal Atatürk. As a result of this, the British authorities did use any of the – mostly documentary – evidence on Armenian atrocities of which Turkish prisoners had been accused and convicted by Turkish military courts shortly after the armistice. Ottoman military members and high-ranking politicians convicted by the Turkish courts-martial were transferred from Constantinople prisons to the Crown Colony of Malta on board "Princess Ena" and HMS "Benbow" by the British forces, starting in 1919. Admiral Sir Somerset Gough-Calthorpe was in charge of the operation, together with Lord Curzon; they did so owing to the lack of transparency of the Turkish courts-martial. They were held there for three years, while searches were made of archives in Constantinople, London, Paris and Washington to find a way to put them on trial. However, the war criminals were eventually released without trial and returned to Constantinople in 1921, in exchange for 22 British prisoners of war held by the government in Ankara, including a relative of Lord Curzon. The government in Ankara was opposed to political power of the government in Constantinople. They are often mentioned as the "Malta exiles" in some sources.