25 July 1975
The Progressive Reform Party (PRP) was formed in the wake of the merger between the Progressive Party and the Reform Party. The decision to merge was made at simultaneously held congresses in Johannesburg. The merger of the two parties was unanimously approved and the leader of the Progressive Party, Colin Eglin, was elected as leader. The party secured eleven seats in the 171-member House of Assembly.
References

Theodor Hanf, Heribert Weiland and Gerda Vierdag, ' Progressive Reform Party (PRP)', in South Africa: The prospects of peaceful change:An Empirical Enquiry into the Possibility of Democratic Conflict Regulation, pp. 101 & 116.|Kenani , (2008), 'Progressive Reform Party', in World Spinner, 27 February [Online], Available at: worldspinner.net, Accessed: 24 July 2013|Amy McKenna, (2009), 'Progressive Federal Party (PFP)', from Encyclopedia Britannica, 14 April [Online], Available at: www.britannica.com [Accessed: 24 July 2013]