To a casual observer, he might have been one of then president Thabo Mbeki's security guards, always within easy reach but performing a task not necessarily discerned by the man in the street.

Having served under Nelson Mandela as an ambassador and under Mbeki as chief of state protocol, Billy Modise was arguably one of SA's most powerful diplomats, a man who knew Mbeki's diary inside out and was intimately involved in the functioning of his office.

"I interacted directly with heads of state whenever they had to meet our president, " he recalls just days after taking retirement.

What he doesn't want to dwell on is how he had to intervene when guests of the president quibbled about seating arrangements. Modise is thin on detail; he is, after all, the diplomats' diplomat, willing only to generalise.

"Some heads of state demanded to choose which country to sit next to and I diplomatically refused ."

It was Modise's job to ensure states represented in SA enjoyed their privileges and immunities. Any issue relating to them had to be reported to him. For instance, police could not arrest diplomats without his approval. He had the ear of the president on this and other sensitive matters.

Modise - ambassador to Canada during the Mandela presidency - had to order the release of an envoy arrested for attempted rape after the ambassador from the foreign country called him to complain. "I immediately called the police station, instructing the officers to release him right away and send me a report of what had happened.

"I then wrote to the ambassador informing him of the [alleged] crime and that they should grant us permission to charge him. The country agreed, otherwise I was going to use my powers to recommend that the person was never to be allowed to set foot in South Africa again."

At 75, Modise is possibly one of the best-dressed seniors in the country. And former presidential spokesman Bheki Khumalo said this sartorial elegance had been consciously cultivated. "I represent the president and the country, so I have to look good," Modise is said to have told Khumalo.

Khumalo speaks as highly of Modise's ability to make tough decisions quickly: "Protocol is protocol; he could read the political situation and be able to make decisions on the spot."

Modise started practising his go-between role when he arranged the emotional meeting between Mandela and Oliver Tambo in 1990. The two ANC veterans had not seen each other since the 1960s, when Tambo fled into exile and Mandela had been sent to Robben Island.

The reunion had to be handled carefully. Tambo had suffered a stroke in London and, with hundreds of people eager to see him in his sick bed, Tambo could not get the rest he required.

It was agreed that Modise, who had represented the ANC in Sweden, should spirit Tambo away to a hospital there, where it would be easier for Modise to control visits. "So when Mandela, together with Walter Sisulu and Govan Mbeki visited, they were received by me."

After 27 years apart, Madiba walked into Tambo's hospital room and they shouted at one another: "Is that you man?"

"They wanted to sleep [in the same room] but I suggested that they could not because Tambo was sick and needed to rest. I allowed them to be together during the day but at night Madiba had to leave," Modise said.

His own political involvement dates back to 1955 when, as a student at the University of Fort Hare, in Eastern Cape, he joined the ANC.

Orphaned since 11, a teacher paid for him to go to university, where he met the likes of ANC stalwart Professor ZK Matthews. Soon Modise was on the frontlines, fighting for the rights of students and raising funds for the treason trialists.

When he won a scholarship to study medicine in Sweden, he again threw himself into student politics.

"Lecturers at the university called me in and said, 'At the rate you are going, you will not make it. We are not going to expel you; you can keep your scholarship but change to social sciences.'

"At the time, I was [travelling] all over Sweden raising funds for the ANC, and the money went to our headquarters in London."

He ultimately completed his master's in sociology.

Modise enjoyed working with both Madiba and Mbeki, but Mandela was difficult work. "He enjoys chatting to people and he can walk into a crowd if not managed."

Mbeki was a good researcher. "It has been difficult for him to release me because I was able to discuss anything with him and I knew when to give him his space."

Modise dedicated his time after retirement to community work and playing golf. Most of his life has been about the country and other people; finally it was all about him.