The Beira Patrol was a blockade of oil shipments to Rhodesia (now Zimbabwe) through Beira, Mozambique, resulting from United Nations trade sanctions on Rhodesia. Background Rhodesia's government unilaterally declared the former colony's independence on 11 November 1965, after rejecting British preconditions for independence that involved racial equality and rule by the black majority. Ian Smith, the country's elected prime minister, continued in that role. The United Nations Security Council reacted by passing Resolution 217, calling for sanctions on Rhodesia. The resolution was later used by the British as legal justification for the blockade. Britain imposed its own national sanctions, including an oil embargo, but ruled out invading Rhodesia. The British were initially opposed to military action, instead relying on UN sanctions to pressure the Rhodesians. A majority of UN member states wanted expanded sanctions and military measures. The British initially attempted to block such initiatives. In October 1965, the Joint Intelligence Committee estimated that even a full trade embargo would fail to cripple Rhodesia's economy due to sanctions evasion enabled by Portuguese Mozambique and South Africa, but suggested that prolonged and severe economic pressure could induce the white electorate to overthrow the government. In early 1966, Prime Minister Harold Wilson made statements that sanctions were working, predicting that the Rhodesian government would soon fall. At the same time, the Foreign Office was feverishly negotiating with the Portuguese Government to participate in the sanctions, which would effectively impose a total blockade on Rhodesia. By the end of 1966, when it became clear that Portugal was unwilling to cooperate against Rhodesia, the Royal Navy began looking into the possibility of a maritime blockade against Mozambique-bound ships carrying oil destined for Rhodesia. During the first week of February 1966, it became clear that Rhodesia continued to import oil by land from Portuguese Mozambique, and Prime Minister Wilson was warned that black African states could push for more urgent sanctions and raise the matter at the UN. On 24 February, the Chiefs of Staff Committee warned that tankers with oil for Rhodesia could arrive in the port of Beira, the terminus of a pipeline going to Rhodesia, unnoticed, and began preparing a maritime surveillance plan for submission to the Prime Minister. Later in February, the British government and world press began focusing on tankers carrying oil for Rhodesia when on 25 February, the Rhodesian Commerce and Industry Minister announced that a tanker with oil