Operation Anvil (Mau Mau Uprising) authorities. Within 48 hours the British had detained 206 known insurgents. In the following weeks over 50,000 Africans were detained and questioned. Nevetheless, numerous leading figures among the rebels managed to escape from Nairobi into the countryside. The operation ended on 26 May. Operation Anvil marked a turning-point in the British campaign against the Mau Mau. The action left the insurgents mostly isolated in the forested mountains of Nyandarwa and Kirinyaga without access to supplies and the assistance of passive supporters. It proved to be the most sophisticated undertaking of the Kenyan Emergency. In the following weeks Mau Mau activity
Mau Mau Uprising as "a complete blueprint for winning the war against Mau Mau using socioeconomic and civic reform." What developed, however, has been described as a British gulag. The Pipeline operated a white-grey-black classification system: 'whites' were cooperative detainees, and were repatriated back to the reserves; 'greys' had been oathed but were reasonably compliant, and were moved down the Pipeline to works camps in their local districts before release; and 'blacks' were the so-called 'hard core' of Mau Mau. These were moved up the Pipeline to special detention camps. Thus a detainee's position in Pipeline was a straightforward reflection of how cooperative