18 November 1988
Popo Molefe, Patrick Lekota and Moses (Moss) Chikane, collectively known as the "Big Three", were arrested in April 1989 and charged with treason. At the time of their arrest the country was rife with unrest. School, rent and consumer boycotts, which culminated in widespread rioting followed by clashes between police and civilians, were common, particularly in the Vaal Triangle. The government accused the United Democratic Front (UDF) as being responsible for the unrest and arrested UDF officials Lekota, publicity secretary, Molefe, national secretary, and Chikane, Transvaal Provincial secretary, together with more than twenty other suspects. Though several were released on bail after one year, the Big Three were kept in Pretoria Central Prison. The accused were charged with treason, the intention being to overthrow the government by unconstitutional means. They were trialed in Delmas, Eastern Transvaal (now Mpumalanga). Lekota, Molefe, Chikane and Tom Manthatha were found guilty of treason on 18 November 1988. On 8 December 1988 Judge Van Dijkhorst sentenced the eleven Trialists. The sentences ranged from ten to twelve years' imprisonment.
References

African Political History: a chronology of key political events from independence to mid-1997, Westport: Greenwood.|

nytimes, 'The Big Three are convicted of treason' ,[Online]Available at:www.nytimes.com [Accessed on 11 October 2013]