The commission has also released a government document from 1986 which recommended that Nelson Mandela should be released from jail only after he became too physically weak to pose a political threat to the apartheid regime.

Schalk van Rensburg, a researcher at the laboratories producing the weapons, told the hearing that it was his understanding that toxins would be used to induce brain damage in Mr Mandela.

The commission was also told of projects carried out at the laboratories where toxins, bacteria and lethal chemicals were concocted for use against political opponents.

The products included cigarettes dipped in the deadly anthrax bacteria and chocolates poisoned with cyanide.

The commission heard evidence that anthrax and cholera had been used to kill numbers of anti-apartheid activists inside and outside South Africa.

A commission member told the BBC that the South African Defence Forces had used cholera extensively in Angola, and that anthrax had been used to infect the food of three Russian advisers in Zimbabwe, one of whom had died as a result.