On 31 July 1979, eight weeks before handover to the Second Republic, the Federal Military Government under General Olusegun Obasanjo announced the nationalisation of British Petroleum's 60 % equity in BP-Nigeria — the joint-venture operator of the Forcados terminal and a major OML 28 producer. The seizure, formalised through the Nigerian National Petroleum Corporation, transferred the assets to NNPC without compensation pending review.
The trigger was BP's role in oil deliveries to South Africa in defiance of the 1977 UN voluntary oil embargo, documented in the Bingham Inquiry (UK Department of Energy, 1978) which found that BP and Shell had sustained apartheid energy supply via Mozambican refinery 'swaps' throughout the post-UDI Rhodesian sanctions period. Foreign Minister Henry Adefope timed the announcement for the opening of CHOGM Lusaka, where Nigeria's delegation under Obasanjo personally pressed Margaret Thatcher on the Lancaster House Rhodesia talks. The nationalisation gave Lagos decisive leverage: within ten days the Lancaster House Agreement on Zimbabwean independence was signed.
BP was paid token compensation in 1991 under the Babangida government's reconciliation package; the company did not re-enter Nigerian upstream until 2003. The episode remains the single most consequential exercise of Nigerian oil leverage in the country's diplomatic history. See United Kingdom relations and South Africa relations.