According to Wikipedia: "The Centurion tank was in use by the South Africans since 1957 – at first, 250 Mk 2 and Mk 3 Centurions bought directly from the UK, but later, South Africa bought Mk 5 Centurions from India and Jordan. Starting in 1970, the UN imposed ever-more-restrictive arms embargoes on South Africa, due to its apartheid practices and human rights violations. This forced South Africa to develop its own arms industry (with surreptitious help from Israel, France and the United States) and this included upgrading the Centurion tanks. Until the 1980s or so, South Africa's enemies had nothing to compare to the tanks that the South Africans were fielding at any particular time. The South Africans improved and upgraded their tanks throughout the Border War in Namibia and Angola."