"even nuke him if it came to it, because we are reputed to have that weapon too"

From the 1960s to the 1980s, South Africa researched and developed nuclear, biological and chemical weapons.  Six nuclear weapons were assembled during the 1980s. South Africa was able to mine uranium ore domestically, and employed enrichment techniques to produce weapons-grade material.  Weapons were tested in the Kalahari Desert, and a high-security weapons research and development facility was established at Pelindaba

Pelindaba Nuclear Facility
GNU Free Documentation LicensePelindaba Nuclear Facility - Credit: NJR ZA

In 1977, the Soviets uncovered evidence that suggested South Africa was preparing for a full-scale nuclear test.  Western governments and the Soviet Union placed strong pressure on  South Africa not to proceed.  The test site was subsequently shut down. In September 1979, a US satellite detected a double flash over the Indian Ocean that was suspected, but never confirmed to be a nuclear test.  There was much speculation that South Africa has carried out a nuclear test, possibly in collaboration with Israel, but this was never confirmed.  South Africa dismantled its nuclear weapons' program in 1989, and acceded to the Nuclear Non-Proliferation Treaty.