The Allies decided on the treaty that was to be imposed on the Ottomans at the Conference of San Remo (19–26 April 1920). The treaty was very much a British creation, with a small input from the French. The Italians had little input into its provisions. American influence on the treaty, as will be seen below, was deliberately prevented. The basic form of the treaty was set in a bilateral meeting between the British and the French on 22 and 23 December 1919. Neither the Italians nor the Americans were invited. During the Supreme Council deliberations Britain and France continued to meet outside the conference sessions to decide what would become treaty provisions.

There was an elaborate procedure for the creation of the treaty, with committees and debates at many bureaucratic levels, but the treaty's main provisions were decided on 22 December 1919 when Philippe Berthelot, Chief Secretary for Political and Commercial Affairs at the French Foreign Office, and Lord Curzon, British Secretary of State for Foreign Affairs, met in London to set the terms of the upcoming treaty with the Ottoman Empire.

Curzon and Berthelot decided that Istanbul was to be lost to the Ottomans, although the sultan might be allowed some sort of fictitious sovereignty. It was to become the capital of an International State of the Straits, completely under Allied control.