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 discuss local affairs in English. In 1948 the Federation changed its name to the Northern Rhodesia Congress and Godwin Mbikusita Lewanika, who had an aristocratic Barotse background, became its first president. In the late 1940s several local trade unions representing African miners merged to form the Northern Rhodesian African Mineworkers' Union. Under Mbikusita Lewanika, Congress gradually developed as a political force. It had some radical policies, but Mbikusita Lewanika favoured gradualism and dialogue with the settler minority. In 1950 and 1951 he failed to deliver a strong anti-Federation message and in 1951 Mbikusita Lewanika was voted out of office and