 The Southern Rhodesians presumed that in the event of Federal dissolution , they would be first in line for independence , and would receive it without major adjustments to their 1961 constitution . Indeed , intergovernmental correspondence during early 1963 did much to confirm Salisbury 's belief that this was the case . While Federal break @-@ up talks progressed , Sandys issued a letter of intent in which he said that powers conferred on the Federal government by British legislation would transfer to Southern Rhodesia at the end of Federation . It was agreed that Salisbury would keep the Federal overseas missions in Pretoria and Lourenço Marques , as well as the British Embassy desks in Bonn , Tokyo and Washington . Arrangements for Federal dissolution concluded in mid @-@ 1963 , and the Federation formally ended on 31 December that year . Northern Rhodesia and Nyasaland became independent during 1964 , respectively renamed Zambia and Malawi , under black majority governments . Southern Rhodesia was denied the same on the grounds that whites held too dominant a position , prompting indignation and fury from the governing Rhodesian Front ( RF ) and its supporters . Prime Minister Winston Field 's failure to secure independence from Britain during early 1964 led to his forced resignation and replacement by his deputy , Ian Smith , in April that year . 
