17 March 1950
Suppression of Communism Act 44 of 1950: One of the most infamous of all security laws during the apartheid era, it severely limited what the media could report through banning threats and the silencing of individuals and organisations. It is under this law that the  Communist Party of South Africa (CPSA). was banned in 1950.  On 20 June 1950, only a few days before the Suppression of Communism Act became law, Sam Kahn announced in the House of Assembly that the CPSA had disbanded. The decision to voluntarily disband was made on 4 May by the CPSA’s central committee, which met in Cape Town (15 votes to 2 votes). By this step the party wished to ensure that its assets would not be confiscated by the state and that Sam Kahn and Fred Carneson would retain their seats in the Assembly and Cape Provincial Council. In response to this, the government amended the act in 1951 to people who had been communists at some previous stage in their lives. In May 1952 Kahn and Carneson were expelled from the House of Assembly and Cape Provincial Council, respectively.
References

South African History Online, ‘Suppression of Communism Act, No. 44 of 1950 approved in parliament’, [online], available www.sahistory.org.za (Accessed: 14 February 2013)|

O’Malley, P. ‘1950’, from Nelson Mandela Centre of Memory, [online], available, at www.nelsonmandela.org.za (Accessed: 14 February 2013)