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
Operation Anvil (Mau Mau Uprising) in the process. Erskine intended on relocating all Kikuyu, Embu, and Meru people from Nairobi, but the colonial government rejected the plan, citing potential harm to the local economy and administration. The operation was based on one British security forces had conducted in Tel Aviv, Palestine. Its legality was assured by the Emergency Regulations and the Control of Nairobi Regulations of 1954, the latter of which permitted the colonial governor to issue "Evacuation Orders" to remove and detain individuals from the city so they could be screened for connections with the Mau Mau. Four battalions were earmarked for the action.