I first met Abba Kyari in 1977 at Warwick University in England. I had gone there to do law as a second first degree. He had come to do a degree in sociology. I had a pending application to do Law at Cambridge and when the result of that application came and it was positive, I left Warwick during the second semester.

But my five months at Warwick was enough to build a strong friendship with Abba that lasted till his passing. Almost 43 years!

There was a small group of Nigerians at Warwick then, which included former President Yakubu Gowon (who was doing a PhD in Political Science) ; Senator Osereihmi Osunbor (former Senator and Governor); Sitonye Roy Wakama (former Deputy Inspector General of Police) and the lawyer, Desmond Guobadia.

There were a few other Nigerians.

Abba was quite skinny in those days! We became friends very quickly and a life-long bond was formed.

Abba was very simple and humble. He was also very friendly with everyone. He had very litte interest in material things. We had a common interest in politics and I believe it was our socialist political values that cemented our friendship because we were always discussing politics and how to salvage Nigeria right up to his passing.

Abba was also surprisingly sociable for someone who was so self-effacing and we

had a lot of enjoyable and memorable experiences at parties and discotheques! Abba also had a very good sense of humour belied by his often stern visage.

When I left Warwick University for Cambridge, Abba came to Cambridge to introduce me to his friends there as he had studied in the city for his Advanced levels. After graduating from Warwick University, Abba went up to Cambridge to study law. We kept in touch throughout the last 43 years. We ended up together in Lagos in 1982 to attend Law School for a year. When I left Nigeria in 1985 to work in Geneva for 30 years Abba came to Geneva often to stay with me and whenever I was in Nigeria, he made it a point of coming to see me wherever I was.

When I got married in Owo to my wife from Idoani, Ondo State, Abba was my Best-Man. The officiating Vicar was somewhat perplexed because I was a Roman Catholic Igbo, marrying an Anglican Yoruba in an Anglican church with a Muslim Kanuri/Shuwa Arab Best-Man from Borno State!

The officiating Catholic priest in Geneva, Switzerland, two years later, during the baptism of our first son, was equally perplexed when a muslim Abba Kyari and a muslim Muni Attah-Sonibare were the Godfather and Godmother respectively! Abba was a Pan-Nigerian, global citizen, who recognized no boundaries between peoples, be they racial, ethnic, religious, class or political. He made friends with everyone.

Abba was a man of unimpeachable integrity. Absolutely incorruptible! I remember after he got married to his wonderful wife, Kulu, he told me how he showed her his first paycheck so she would know that he was not wealthy and would not steal!

It broke my heart to see all the false allegations against him on issues of corruption. He showed me the safe in his office where he put any unsolicited gift.

I remember asking him about the rumours making the rounds that he was making money from the fine imposed on MTN. He immediately showed me the memorandum setting up the Committee to deal with the issue and he was not even a member. He also showed me how he had been able to block attempts by many influential and powerful persons to make a lot of money at the expense of the country. He knew that fighting corruption with such single mindedness and fearlessness would see him at the receiving end of the venom of very powerful forces but was undeterred and preferred to ignore all the defamation against him.

Abba was loyal to a fault. He decided he was going to protect his boss, President Muhammadu Buhari, at all costs and would take any number of bullets for him. And he did!

Since he became Chief of Staff to the President, Abba never rested. He worked day and night, seven days a week. He was a hard taskmaster who did not suffer fools gladly. A very demanding boss. He gave a lot of himself and expected his subordinates and colleagues to do the same.

He was very intelligent, very well-read and had a wide and varied professional experience. He held strong opinions and did not yield position easily. But once he believed in someone or a cause, he would fight with everything he had.

Abba believed completely in the Nigerian project and believed completely in President Muhammadu Buhari. During the last five years he gave every second of his life for the success of both. His health suffered as a result but it was a sacrifice and investment he was happy to make. Nigerians will look back in years to come and see that he was truly the Best Man.

Rest In Peace my brother.

• Geoffrey Onyeama is Nigeria’s Minister of Foreign Affairs