Mau Mau Uprising attempt to eliminate Mau Mau's presence within Nairobi in one fell swoop. 25,000 members of British security forces under the control of General George Erskine were deployed as Nairobi was sealed off and underwent a sector-by-sector purge. All native Kenyans were taken to temporary barbed-wire enclosures, whereafter those who were not Kikuyu, Embu or Meru were released; those who were remained in detention for screening. Whilst the operation itself was conducted by Europeans, most suspected members of Mau Mau were picked out of groups of the Kikuyu-Embu-Meru detainees by a native Kenyan informer. Male suspects were then taken off for
Mau Mau Uprising it fell to Dr. John Colin Carothers to perform the desired analysis. This ethnopsychiatric analysis guided British psychological warfare, which painted Mau Mau as "an irrational force of evil, dominated by bestial impulses and influenced by world communism", and the later official study of the uprising, the Corfield Report. The psychological war became of critical importance to military and civilian leaders, who waged it in the time-honoured colonial fashion of divide and rule, always trying to "emphasise that there was in effect a civil war, and that the struggle was not black versus white", attempting to isolate Mau Mau from