Newly-released secret British papers show how the Biafran civil war which nearly destroyed the Nigerian federal state 30 years ago, turned into a triangular big-power contest between the United Kingdom, France and the Soviet Union.
About a million Biafrans starved to death because of the blockade applied by the Nigerian federal military government.
The breakaway state of Biafra was declared in May 1967, by the Ibo people of eastern Nigeria.
They were at odds with the rest of the federation and their military governor, Colonel Ojukwu, thought they could survive with revenues from the oilfields in their territory.
But the move was opposed by the federal military government and fighting broke out.
At first Biafra was successful and this alarmed Britain, the former colonial power, anxious for its big oil holdings.
It also interested the Soviet Union which saw a chance to increase its influence in West Africa.
Both sent arms to boost the federal military government, under General Yakubu Gowon.
But France, the other big former colonial power in the region, also took a hand.
Arms from Francophone neighbours
Although Paris repeatedly denied arming the Biafrans, the newly-released papers reveal intelligence reports showing that very large weapon shipments were reaching Biafra via two neighbouring Francophone states, Ivory Coast and Gabon.
The UK intelligence services warned that Soviet penetration was growing but that this did not much trouble Paris.
The British reports says the French objective "appears to be the break-up of Nigeria, which threatens, by its size and potential, to overshadow France's client Francophone states in west Africa".
But the flow of French arms diminished as the Biafrans wilted under relentless attacks and a food blockade.
In January 1970 the secession collapsed, and Colonel Ojukwu fled to Ivory Coast.