Ali Khadr, the World Bank's Chad director, said oil would begin flowing from the country's southern Doba oilfield in July 2003.

However, with transportation and shipping expected to take another three to four months, the first barrels of Chadian oil are not expected to reach international markets until November next year.

The World Bank has partly financed the development of the Doba oilfield, and has also helped to pay for a £2.2bn pipeline designed to carry oil from landlocked Chad to the port of Kribi in neighbouring Cameroon.

The project, backed mainly by US oil giants ExxonMobil and Chevron and Malaysia's Petronas, cost a total of $3.7bn (£2.3bn).

Chad's Doba oil reserves are thought to contain 25 years' worth of supply at an output rate of 225,000 barrels a day.

Chad, one of the world's poorest nations, is expected to make about $2bn from the project over its lifetime.

Cameroon's share of the profits is expected to reach $500m.