Edinburgh dignitaries were in the Olympic host city to have Scotland's capital, sole candidate for the '86 Games, receive the rubber stamp of the Games federation.
Standing outside one of Stalin's hotels, Abraham Ordia, president of the Supreme Council For Sport In Africa (who had orchestrated the 1976 Montreal Olympic boycott), told us he had warned the federation general assembly they were "toying with the unity of the Commonwealth". Rugby tours with the Springboks could provoke another boycott, said the Nigerian.
"Edinburgh Games in jeopardy" read our headline next morning. In an impassioned and emotional interview with The Glasgow Herald, Ordia said: "If you don't respect the rights of millions of people in Africa, you have no right to expect to play sports with them. If you don't want us, we are not begging to stay in the Commonwealth."
The 1986 Games became a notoriously poisoned chalice, and Prime Minister Margaret Thatcher's lack of support for sanctions sealed the predicted boycott, with devastating financial consequences.
Anger over the 1968 Lions' tour of South Africa had drawn an estimated 50,000 demonstrators to Hyde Park, and the following year South African-born Basil D'Oliveira (a Cape-coloured, in the prevailing jargon) was omitted from the England touring side because the Republic had told selectors he would be unwelcome.
D'Oliveira had averaged more than 50 over the three series against West Indies, India and Pakistan in 1966 and 1967. His place in the side seemed assured.
He did less well in the West Indies in 1967-68 but in the first Test against Australia in 1968 he was the only batsman to put up much resistance, scoring 87 not out.
But D'Oliveira's form suffered as pressure was put on him not to tour South Africa that winter, should he be picked.
In September he was eventually chosen to tour and shortly afterwards the South African government publicly announced that an England side containing D'Oliveira would be unacceptable. The MCC called off the tour.
The cricket tour was cancelled and the wheels were set in motion for South Africa to be ostracised from international sport for two decades.
But before the boycott was formalised the Springboks toured the UK in 1969-70. There were protests at many of the matches, by the anti-apartheid Stop The Seventy campaign organised by Peter Hain. Gordon Brown was the group's Edinburgh organiser.
When the Springboks played Scotland, Murrayfield was the focus of a further demonstration following protests around the country.
In 1970 the Cricket Council reversed a decision to allow South African cricketers to tour England that summer. The move followed strong pressure from the then Home Secretary, James Callaghan.
In 1977 the Gleneagles Agreement was unanimously approved by the Commonwealth at a meeting at Gleneagles. Commonwealth presidents and prime ministers agreed, as part of their support for the international campaign against apartheid, to discourage contact and competition between their sportsmen and sporting organisations, teams or individuals from South Africa.
Eight years later isolation had driven Zola Budd to seek a UK passport of convenience for the 1984 Olympics, and the following year she was due to race at Meadowbank. Perhaps keen to make a point that might ensure African participation in the 1986 Games, the city council hung a sign: "Edinburgh Against Apartheid" on the scoreboard. A demonstrator tried to tackle Budd on the track, but with a sidestep that would have done credit to a Springbok fly half, she avoided him.
All to no avail. She missed the British and Commonwealth mile record by half a second; it did nothing to deter a Games boycott; and TV, which had a contract for an advert-free stadium, refused to screen the meeting. Further major televised athletics shunned the capital - coincidentally helping Glasgow become the focus of the sport in Scotland.
Sporting isolation was particularly hard on the South African rugby and cricket community, and Budd was not the only elite athlete to move elsewhere. Marcello Fiasconaro took Italian nationality, setting a world indoor best at 400m, and a world 800m outdoor record.
The release of Mandela brought a return to normal sport relations in 1991 - arguably the greatest example of sport influencing politics for good. Stars from the world of sport paid tribute to Madela.
Yesterday, sporting tributes were led by former South Africa rugby union captain Francois Pienaar. Mandela's appearance in a Springboks shirt and cap to present the 1995 Rugby World Cup trophy to Pienaar was a defining moment in transforming the country into a multi-racial democracy.
It inspired the Hollywood film Invictus, and Pienaar said: "The enormity of his impact is very difficult for me to describe."
"What he did for the team was wonderful to watch - that air of confidence he brought with him and that unbelievable humility Madiba had was something that rubbed off - and I never thought he would wear a Springbok jersey!"