The resignation of Mr F. W. de Klerk as leader of the National Party has moved South Africa a step closer to becoming a de facto one-party state along the lines of Zimbabwe to the north.

As the succession struggle develops in South Africa's former governing party, the immediate beneficiary of Mr De Klerk's resignation, and the damaging blow it inflicted on the morale of the NP, is undoubtedly Nelson Mandela's African National Congress.

Even before Mr De Klerk's resignation, the ANC's political ascendancy was impressive: it won 62 per cent of the vote in the April 1994 election, more than three times that of its nearest rival, the NP.

Mr De Klerk's decision to quit the political arena will strengthen arguments for regarding South Africa as a state in which opposition parties are confined to the periphery, and the hegemony of the ruling party assured for the foreseeable future.

One of the reasons given by Mr De Klerk for resigning was his belief that the NP needed to be freed of the burden of its apartheid past, a legacy with which he recognised he was associated regardless of his role in helping to dismantle the apartheid state.

"I believe that the party needs to rejuvenate itself with fresh leadership," he said.

The implication of Mr De Klerk's reasoning is that a younger leader, untainted with the image of the NP as the progenitor and propagator of apartheid, will be better positioned to lead the party into the new millennium, a process which includes contesting the pending 1999 general election.

Mr De Klerk's prognosis may be proved right in the long run. But his resignation is a major setback to the NP for the immediate future.

None of his possible successors can match his image as a mature politician who rose above the dictates of tribe and caste to win accolades throughout the world and be awarded the Nobel Prize for Peace.

Significantly, none of the contenders in the succession struggle is completely untainted by apartheid, not Sam de Beer, not Danie Schutte, not former Foreign Minister Pik Botha - who has emerged as a late candidate on condition that the party agree to allow him to lead it back into President Mandela's government of national unity - and not Marthinus van Schalkwyk, who has admitted to being a paid agent of military intelligence in the 1980s.

Mr De Klerk's resignation does not come at a high point in the party's fortunes. Since the April 1994 election, the level of its support has declined from 20 to 15 per cent - and even less according to some polls.

The party is in disarray beyond the Western Cape. Successive defeats at the hands of the minuscule Democratic Party in conservative towns where it was once invincible indicate that it is becoming a regional party in all but name.

While the NP is likely to suffer further humiliation at the hands of small parties, there is no evidence that any of the existing parties is poised to make inroads into the ANC's vast constituency. Quite the opposite: the ANC is homing in on Mangosuthu Buthelezi's Inkatha Freedom Party.

Opinion polls put the IFP's national level of support at less than five per cent.

Last year's local government election in KwaZulu-Natal shows that IFP support has declined since 1994, dropping from just 50 per cent to under 45 per cent in the province. Closer scrutiny of the results indicates that it was routed by the ANC in urban areas, a positive sign for the ANC in a country where urbanisation is a dominant sociological trend.

AT the same time, there are signs of a rapprochement between the ANC and the IFP, one which may result in a merger based on a common commitment to Africanism but one which will see the IFP confined to the role of a junior partner - if it is not absorbed as Joshua Nkomo's Zapu was in Zimbabwe when it merged with Robert Mugabe's Zanu-PF.

The immediate future is thus one of continued and probably enhanced ANC dominance, with or without the incorporation of the IFP. The remaining smaller parties seem set to squabble over a declining non-ANC vote.

But, even if they reach an electoral accommodation between themselves, they will be marginalised by the ANC's political preponderance.

The ANC is, of course, an alliance of disparate racial, ethnic, class and ideological forces and is bound, sooner or later, to generate its own opposition by shedding some malcontents. But that, like the hypothetical rejuvenation of the NP, is still a long way down the line.