 Following months of abortive Anglo @-@ Rhodesian talks and unsuccessful attempts by Britain to deter Portugal diplomatically , Reedman travelled to Lisbon in September 1965 to take up his post at the head of an independent Rhodesian mission . The Portuguese Ministry of Foreign Affairs , which insisted it was neutral regarding Rhodesia , outraged Whitehall by accepting Reedman 's letter of accreditation — though Lisbon was careful to avoid provoking Britain , omitting the word " diplomatic " from the titles given to both Reedman and his mission . The Rhodesians still regarded themselves as victorious , saying they had set out to gain an independent diplomatic representative in Lisbon , and now had one . The historian J R T Wood would call this " Rhodesia 's first independent and indeed unilateral act — the veritable straw in the wind . " On 11 November 1965 , less than two months after Reedman 's investiture , Rhodesia went one further and unilaterally declared its independence from Britain . The mission in Lisbon operated until 1975 , when it was closed following the Carnation Revolution in Portugal the previous year . 
