When government auditors searched the offices of Nigeria's Ministry of Petroleum Resources last July, window blinds, a door curtain and an embossing machine that a civil servant drew N474,350 of public funds to buy were missing. The apparent theft, described in a 290-page annual audit seen by the Financial Times, captures the corruption and opacity that characterises governance in oil-rich western and central African states. It partly explains why exploitation of crude reserves in countries such as Angola, Gabon and Nigeria - the latter has earned more than $300bn from oil since independence in 1960 - has yielded little for ordinary people while officials and elites have become richer.