Mau Mau Uprising more mobile formations that delivered what he termed "special treatment" to an area. Once gangs had been driven out and eliminated, loyalist forces and police were then to take over the area, with military support brought in thereafter only to conduct any required pacification operations. After their successful dispersion and containment, Erskine went after the forest fighters' source of supplies, money and recruits, i.e. the native Kenyan population of Nairobi. This took the form of Operation Anvil, which commenced on 24 April 1954. By 1954, Nairobi was regarded as the nerve centre of Mau Mau operations. Anvil was the ambitious
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