Announcing his Cabinet on 17 December 1962, Field named Smith his Deputy Prime Minister and Minister of the Treasury. Two days later, R.A. Butler, the UK's Deputy Prime Minister and First Secretary of State, announced that the UK government would allow Nyasaland to leave the Federation. With Northern Rhodesia now also under a secessionist black nationalist government—Kenneth Kaunda and Harry Nkumbula had formed a coalition to keep the UFP out—and Southern Rhodesia under the RF, the Federation was effectively over. The Field Cabinet made Southern Rhodesian independence on Federal dissolution its first priority, but the Conservative government in the UK was reluctant to grant this under the 1961 constitution as it knew doing so would lead to censure and loss of prestige in the United Nations (UN) and the Commonwealth. Indeed, Southern Rhodesia's minority government had already become something of an embarrassment to the UK and it hurt Britain's reputation to even maintain the "status quo" there. Granting independence without major constitutional reform would furthermore provoke outcry from the Conservatives' main parliamentary opposition, the Labour Party, which was strongly anti-colonial and supportive of black nationalist ambitions.