The McMahon- Hussein Correspondence, was an exchange of letters (14 July 1915 to 30 January 1916) between the Sharif of Mecca, Husayn Bin Ali, and Sir Henry McMahon, British High Commissioner in Egypt, concerning the political status of lands included in the Ottoman Empire.
The letters declared that the Arabs would revolt and in return, and the British would recognize Arab independence in the Ottoman Empire
Source: (March 16th, 1939 Report of Committee set up to consider Certain Correspondence between Sir Henry McMahon [HIS MAJESTY’S HIGH COMMISSIONER IN EGYPT] and The Sharif of Mecca) Cmd.5984