BBC Africa Correspondent Jane Standley reports on the huge gulf separating Angola's rich from its poor

The longest and most miserable civil war in Africa, the fighting that has gripped Angola since 1961 has also been the most misrepresented and misunderstood of the continent's many colonial and post-colonial conflicts.

At various stages, the violence has been characterised as anti-imperial and revolutionary, a Cold War proxy, or a brutal competition between rival elites for a wealth of natural resources.

The real source of the bloodshed, however, is rooted as much in ethnic and historical tensions that stretch back centuries.

The key to an understanding of Angola's civil war lies with the enigmatic and charismatic rebel leader Jonas Savimbi whose National Union for the Total Independence of Angola (Unita) first took up arms against the colonial Portuguese and the two, more established liberation movements, in 1966.

Initially Maoist but later pro-Western, for Unita, like the government, ideology has never been more than a useful tool for better prosecuting the struggle.

Unita emerged because of a perceived dominance of the Movement for the Liberation of Angola (MPLA) by mixed-race intellectuals from the coastal cities, and of the National Front for the Liberation of Angola (FNLA) by northerners.

As independence approached in 1975, each side solicited the support of Cold War patrons, with Cubans helping the MPLA to take the capital, Luanda, South Africans siding with Unita and the United States supporting an increasingly ineffectual FNLA in the north.

Despite criticism of external involvement, in reality it was more a case of the puppets pulling the strings of the puppet masters in a ruthless bid to seize the initiative.

Ethnic tensions

That process of institutionalising tensions based on class, race and ethnicity remains at the heart of the conflict:

• Ovimbundu Unita supporters, mostly in the central highlands, are pitted against the coastal and Kimbundu peoples

• Perhaps equally importantly, Unita claims to represent the 'real Africans', sons of the soil, living in the bush, fighting against a wealthy, cosmopolitan, better-educated urban elite.

• Many Ovimbundu were sent to pick coffee by the Portuguese, who saw them as harder workers, and they still resent light-skinned people, or mesticos, who make up a significant proportion of the urban population.

• The military logic of war, which has kept Unita's guerrillas in the countryside and restricted the better-armed MPLA to the cities, serves to entrench this fundamental division.

Angola's children face a bleak future

In this context, Angola's ample natural resources - diamonds in the north east and crude oil in offshore waters - have similarly proved little more than a device to prolong a civil war that benefits a narrow elite on both sides.

Peace agreements reached in 1974, 1989, 1991 and 1994 have all collapsed, leaving a country laid waste by war and a generation that has known nothing but conflict.

Much of the responsibility must lie with the intransigence of political personalities on all sides so ready to exploit those fundamental cleavages within society that are as sharp today as when the fighting first began.