26 November 1975
On an illegal trip to South Africa with a false passport, a well-known Afrikaans writer Breyten Breytenbach was betrayed, arrested and sentenced to nine years imprisonment for high treason under the Terrorism Act by the Pretoria Supreme Court. He had pleaded guilty for entering South Africa to start an organisation Atlas or Okhela, a resistance group fighting apartheid in exile and was intended to be the White wing of the banned African National Congress (ANC). He remained a political prisoner until his release in December 1982 amid strong international intervention.
References

Kalley, J. A. et al (1999). Southern African Political History: A Chronology of Key Political Events from Independence to Mid-1997, Greenwood: London, p. 412.