There is no need for the scare-quotes around "know" - President de Klerk gave a speech in which he admitted that South Africa had built and subsequently dismant

There is no need for the scare-quotes around "know" - President de Klerk gave a speech in which he admitted that South Africa had built and subsequently dismantled a nuclear weapons program. There are public IAEA reports on the verification process following SA's accession to the NPT. (An interesting insight into late cold-war politics is that it was the Soviet Union that tipped off the United States that South Africa was preparing to test a weapon).