Lt-Col Odumegwu Ojukwu declared the Republic of Biafra on 30 May 1967, citing the failure of the Federal Military Government to implement the Aburi Accord (January 1967) and the inability of the federation to protect Easterners after the 1966 pogroms. Federal operations opened on 6 July 1967. In August 1967 Biafran forces crossed the Niger, seized Benin City and briefly threatened the route toward Lagos before federal troops pushed them back; the Midwest invasion is widely regarded as the strategic turning point that hardened federal resolve and cost Biafra the Atlantic outlet. Port Harcourt — Biafra's last access to oil revenue and seaborne supply — fell to the 3rd Marine Commando Division in May 1968.
From September 1968 the ICRC ran a large-scale airlift into the Uli airstrip — at its peak the second-busiest airport in Africa by night-time movements — alongside the parallel Joint Church Aid 'Jesus Christ Airline.' Five states recognised Biafra: Tanzania (13 April 1968), Gabon, Côte d'Ivoire, Zambia and Haiti, across 1968–69. The war lasted 30 months. A federal blockade — including of relief shipments — caused mass starvation, immortalised in photographs by Don McCullin and others. Estimates of dead range from 500,000 to over 3 million, predominantly of starvation and disease.
Ojukwu handed over to Maj-Gen Philip Effiong and left for exile in Côte d'Ivoire on 10 January 1970; Effiong led the Biafran delegation to Lagos and Nigeria accepted the surrender on 15 January 1970 at Dodan Barracks. The post-war "£20 policy" — under which any Biafran bank balance, regardless of size, was exchanged for a flat £20 — wiped out Igbo savings overnight; no truth commission or formal reconstruction programme was implemented at federal level. Gowon's "No Victor, No Vanquished" speech and the Three Rs (Reconciliation, Reconstruction, Rehabilitation) framed the official close, but the structural exclusion of the post-war Igbo from significant federal and military positions for much of the next two decades is part of why the civil war remains, in the Nigerian memory, a continuing reference point rather than a closed historical episode.
Figure 1
Biafra War deaths by cause, 1967–1970 (mid-range estimates, thousands)
The federal blockade — not the front line — killed roughly seven of every eight Biafran dead. The mid-range death toll is two million; the upper bound is three.
Source: ICRC field reports 1968–70; de St. Jorre, The Brothers' War (1972); Heerten & Moses (eds.), Postcolonial Conflict (2017).