Mr de Klerk, parliamentary sources said, blew his top, berating the MP for his defeatist talk and protesting that not only he but all serving Nationalist MPs would retain their seats under a new democratic dispensation.
The President's uncharacteristic display of pique was symptomatic of his political responses in recent weeks. As opposition voices in parliament have been saying, he is panicking at the prospect of the National Party centre falling apart. The defection to the right-wing of just 12 of his MPs, he knows only too well, would lose the party its parliamentary majority.
Yesterday Mr de Klerk's credibility was dealt a blow by the fracas following his unilateral appointment of a new chairman for the South African Broadcasting Corporation (SABC).
Impartial control of the SABC, the state media monopoly, is considered by all the main political players to be imperative at a time when the country is supposed to be heading for democracy. Last week an independent panel of judges chosen to select a new SABC board gave Mr de Klerk a list of recommendations - the general understanding having been that he would simply rubber stamp them.
Instead Mr de Klerk, sticking - as his critics have said - more to the letter than to the spirit of the law, changed a number of the names, including that of the chairman. The judges had put forward a black academic, Njabulo Ndebele, as their choice. Mr de Klerk announced on Monday that the new chairman would be Frederik van Zyl Slabbert, a former leader of the liberal Progressive Federal Party, widely seen today to be the country's most perceptive political analyst. On Monday night Mr van Zyl Slabbert, who heard of his appointment on the radio, announced he would not accept the position.
Yesterday the African National Congress (ANC) accused Mr de Klerk of 'gross interference' and demanded he abide by the judges' initial recommendations. Mr van Zyl Slabbert described the situation yesterday as 'untenable' and a 'mess'.
Mr van Zyl Slabbert noted that where the President was most vulnerable now was on his right flank. 'He sees the generals getting the right- wing together and the right-wing warrior class gathering on the streets of Pretoria.'
At a time of deepening discontent in the National Party at what is perceived to be Mr de Klerk's betrayal of the Afrikaner volk to the ANC, a group of former generals has started actively engaging in politics, striving with some apparent success to unite the right against the government.
It was in the light of this right-wing resurgence that numerous commentators in South Africa have interpreted the decision of the police high command last week to arrest almost the entire leadership of the radical Pan-Africanist Congress, a move that had a direct impact on the failure of multi-party negotiators to meet a self- imposed deadline for announcing an election date. The deadline was to have been tomorrow, but with talks in the past week having focused almost entirely on rebuilding the trust lost by the action against the PAC, it was pushed back to 25 June.
Mr de Klerk's endorsement of the police swoop has been interpreted as a sign of his unwillingness to antagonise the right further and, as Mr van Zyl Slabbert noted yesterday, of the grave difficulties he faces in bringing the security forces into his reformist programme.
Kobus Jordaan, an MP of the centrist Democratic Party and a constant critic of the security forces, said yesterday that all Mr de Klerk's actions these days had to be seen in terms of his instinct to look over his right shoulder. 'The problem also is that he still acts in the old National Party style - the man at the top's word is law. His frame of mind reflects his view that he heads South Africa's legal government. What he cannot understand is that the key now in politics is not legality but legitimacy.'