The death of Dr Treurnicht, known as 'Dr No' for his consistent opposition to government reforms during the last decade, will be a severe blow to the party that has been the official opposition since 1987, according to parliamentary sources. Tensions between moderates, who seek a negotiated accommodation with the black majority, and hardliners more politically inclined towards the firebrand politics of Eugene Terre-Blanche, seem likely to lead to a split.
Treurnicht's heir-apparent, the deputy party leader Ferdi Hartzenberg, is a less sophisticated, more rigid politician than Treurnicht, who was seen as a stabilising force on the factious South African right.
The conclusion was irresistible last night that Treurnicht's death had been accelerated by the arrest of the Conservative Party stalwart Clive Derby-Lewis on Saturday in connection with the assassination of the African National Congress leader Chris Hani. Treurnicht, who stood up to those in his party and beyond who advocated political violence, was close to Mr Derby-Lewis, with whom he went on a European tour in 1989.
In recent months Treurnicht had softened his party's traditionally inflexible stance, agreeing to do what he had previously vowed never to contemplate - participate in multi-party constitutional talks with the ANC and their Communist Party allies. His party's central demand remained extreme and unlikely to be met - an independent 'Boer' nation outside 'the new South Africa' - but at least, as his political opponents note, he had persuaded his party to seek the road of peaceful negotiation.
Treurnicht, who became a minister of the Dutch Reformed Church in 1946, had by his own standards moderated his political tactics - if not his bedrock apartheid beliefs - in later life.
An important clerical ally in the Sixties of the architect of apartheid, Hendrik Verwoerd, he became a member of parliament of the long-ruling National Party in 1971. In 1976, as deputy minister of Bantu Education, he insisted that black children should receive more of their education in Afrikaans, an insensitive position which sparked the Soweto riots that year and galvanised what in previous years had become a relatively moribund, shackled, black liberation movement.
Opposing the decision of the prime minister, P W Botha, in the early Eighties to admit Asians and mixed- race Coloureds to parliament, he quit the National Party with 15 other MPs in 1982 and formed the Conservative Party. He improved his party's parliamentary representation both in the 1987 and 1989 whites-only elections but suffered a crushing reverse a year ago when, in a national referendum, an overwhelming majority of whites voted for President F W de Klerk's proposals for sharing power with the black majority.
That seemed to be the end for Treurnicht. But he entered into a loose alliance - the Concerned South Africans Grouping (Cosag) - at the end of last year with Mangosuthu Buthelezi's Inkatha Freedom Party and other right-wing black leaders. Cosag has since fallen by the wayside and the Conservative Party has headed back into the white laager, striving, increasingly hopelessly, to push peacefully for a Boer republic.
South African police yesterday released two more of the people detained in connection with Hani's murder. Still detained are Mr Derby- Lewis, his wife, Gaye, and the alleged gunman, Janusz Walus.