Following the sad death of Nelson Mandela at the age of 95, the Oxford Martin School's Director, Professor Ian Goldin, reflects on the time he spent working with the former South African President, who led his country to democracy after serving 27 years in prison. This article was first published by OECD Observer

President Mandela stands in the pantheon of political leaders. He was blessed with an extraordinary ability, intelligence and memory, but it was his character that sets him head and shoulders above other leaders.

Modesty, patience and a genuine interest in ordinary people, honed from his 27 years in prison made him unique, as did his relentless honesty and upholding of principles of human rights. It was these ideals that placed him in prison in the first place, after he refused to bow to apartheid.

Having met Nelson Mandela soon after his release from prison on his first visit to Paris, when I was at the OECD from 1988 to 1992, it was a dream come true to be invited to join his government as the CEO of the state-owned Development Bank of Southern Africa, which became the most significant provider of municipal and infrastructure finance in southern Africa. It was a privilege to be intimately involved in discussions on economic policy and to accompany President Mandela on numerous state visits, including to France and the UK, and to engage on his behalf in other activities, such as taking the financial lead for South Africa’s Olympic Bid. South Africa did not win the bid, but as with the decisions to host the rugby and football World Cups, Mandela understood that beyond the essential economic benefits, the widely shared love of sport could heal the wounds of a racially divided nation seeking to overcome the legacy of apartheid.

President Mandela was an extraordinary listener, with the razor sharp mind of a top trial lawyer delving into every detail of an issue until he had mastered it. Once this was the case, he had a remarkable ability to retain facts and conversations. So, for example, in a conversation he was keen to drill down with me into the significance of savings and interest rates and then years later repeated the arguments in response to a media question. Under President Mandela’s leadership, the ruling African National Congress party transformed its economic policies to allow for the full integration of South Africa into the global economy and the establishment of sustainable macroeconomic policy. The economy reduced protectionism that had been reinforced by apartheid sanctions and high tariff walls and became the driver of economic growth in the Southern Africa region, as well as a leading member of the reinvigorated African growth strategy and a key member of the BRICS.

While having a finely tuned understanding of politics and an encyclopaedic knowledge, Mandela was a great leveller, making a point of calling all Presidents (and even royalty) by their first names, and invariably flummoxing security by heading into the kitchens to thank the chefs or into the offices to thank a secretary. His charisma and natural ability meant that everyone–including Queen Elizabeth and Presidents Bill Clinton and Jacques Chirac–felt humbled in his presence.

He was a towering personality with a beautiful mind, who endured too much. The world badly needs great leaders. The tragedy of Mandela’s passing is that it underlines the rarity of his extraordinary combination of courage, commitment, charisma, intelligence, self-sacrifice and, rarest of all, wisdom.

Nelson Mandela, president of South Africa from 1994 to 1999, was born in Mvezo, South Africa, on 18 July 1918, and died in Johannesburg, South Africa, on 5 December 2013, aged 95.

Ian Goldin worked at the OECD from 1988 to 1992

• This article was first published on the OECD Observer website