30 September 1963
Tanganyika (now known as Tanzania) formally ended all direct and indirect trade relations  with South Africa. Tanganyika became one of the first countries in Africa to impose sanctions on South Africa. The majority of countries in the western bloc and all those making up the eastern bloc were first to impose sanctions against South Africa in the 1960s. Only the United States (US) and the United Kingdom (UK) continued their friendly relations with South Africa for much of the 1970s. It was not until the call for sanctions against and disinvestment from South Africa became part of a wider, global political campaign that the US and UK heeded the call for a boycott of the apartheid state.
References

Ngeleza B. and Nieuwhof A. (2004), ‘Sanctions against apartheid South Africa should inspire the Palestinian people’, from Electronic Intifada, 14 December, [online], available at https://electronicintifada.net  (Accessed: 3 September 2012)|

 O’Malley P. ‘1963’, from Nelson Mandela Centre of Memory and Dialog, [online], available at www.nelsonmandela.org.za (Accessed: 3 September 2012)