Diezani Alison-Madueke, 65, was found not guilty after a trial at London's Southwark Crown Court of five counts of accepting bribes and a charge of conspiracy to commit bribery. Alison-Madueke was Nigeria's oil minister between 2010 and 2015 and the first female president of the oil exporters group Opec.
The verdict is a blow for the UK's National Crime Agency (NCA), which had been investigating one of Africa's most prominent political figures for 13 years.