One of her greatest achievements was leading a team which negotiated a whopping $18bn debt right-off in 2005 for the country, helping Nigeria obtain its first ever sovereign debt rating.

The country's debts had dated back to the early 1980s, and had ballooned to more than $35bn due to penalties and late fees during the 1990s.

Her economic reforms had a far-reaching impact and saved Nigeria at a critical period, according to prominent Nigerian economist, Bismarck Rewane.

This included de-linking the budget from the oil price, allowing the country to save money in a special account when oil prices were high.

"It was this buffer that ensured Nigeria's economy survived between 2008 and 2009," Mr Rewane told the BBC.

Ms Okonjo-Iweala had given up a well-paid job at the World Bank and left her family in Washington, where her husband works as a neurosurgeon, to work in Nigeria, where unlike other ministers she did not have a large domestic staff or fleet of cars.

In fact she even liked doing her own cooking when she could, with cowtail pepper soup being a favourite, a Financial Times interview revealed in 2015.