Northern Rhodesia had been detained without trial, following claims that they had planned the indiscriminate killing of Europeans and Asians, and of African opponents, the so-called "murder plot". Shortly afterwards, on 12 March 1959, the governor of Northern Rhodesia also declared a State of emergency there, arrested 45 Zambia African National Congress including Kaunda and banned the party. Kaunda later received a 19-month prison sentence for conspiracy, although no credible evidence of conspiracy was produced. The declaration of States of emergency in both Northern Rhodesia and Nyasaland marked the end of attempts by their nationalist parties to work within the colonial system,
Northern Rhodesia Ila and plateau Tonga peoples, but the United National Independence Party was dominant elsewhere. Roy Welensky, a Northern Rhodesian settler who was the Federal Prime Minister from November 1956 had convinced Alan Lennox-Boyd, Colonial Secretary from 1954 to 1959, to support Federation and to agree that the pace of African advancement would be gradual. This remained the view of the British cabinet under Harold Macmillan until after the declaration of the States of emergency, when it decided to set up a Royal Commission on the future of the Federation of Rhodesia and Nyasaland to be held in 1960. This became