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 for self-determination in 1922, this objection ceased, and in 1927 the Conservative Colonial Secretary, Leo Amery gave Southern Rhodesia settlers the impression that he supported their claim to acquire the more productive parts of Northern Rhodesia. At the end of the First World War, the European population of Northern Rhodesia was tiny, about 3,000 compared with ten times as many in Southern Rhodesia, but it increased rapidly after the discovery of the Copperbelt in the 1920s. Northern Rhodesian settlers wanted self-government for the European minority electorate, separate from Southern Rhodesia. However, once the British government appeared to reject the idea