Jeremy Hunt’s 12,500-mile odyssey through Ghana, Senegal, Nigeria, Ethiopia and Kenya has been a chance for the man who could be the UK’s next prime minister to learn more about Africa – and for us to learn more about him.

The visit by the foreign secretary was ambitious in mileage and scale, speckled with meetings with presidents, helicopter rides to Maiduguri – the Boko Haram haven in Nigeria’s north-east – keynote speeches at the African Union headquarters, seminars with civil society and photo-ops.

Meticulously planned, it ended with a visit to the HIV educational charity he helped fund in Kibera in the slums of Nairobi from the proceeds of his business. He is greeted as a long-lost friend and Honourable Jeremy. The children speak eloquently to him about the stigma of HIV.

Facebook Twitter Pinterest Hunt visits Kibera in western Nairobi, Kenya. Photograph: Harriet Line/PA

The themes of the visit are also large: climate change, Africa’s population explosion, the shift of the jihadist frontline from Syria to Lake Chad, media freedom and the role of modern authoritarian China on the continent.

Throughout, there is the backdrop of Brexit and startling news from home of the sacking of the defence secretary, news relayed to him on landing in Ethiopia that lifted a cloud of suspicion that he had been the leaker from the inner sanctum of the national security council.

It is a test of Hunt’s poise and depth. Through the week some pieces fall into place.

He will not talk leadership – “there will be a time for that” – but this man is running for sure. The very fact that his Chinese wife Lucia Guo has accompanied him, with the pair leaving behind their three young children for a week, is a clue.

Facebook Twitter Pinterest Hunt attends a tree-planting ceremony in Ethiopia on his tour of Africa alongside his wife Lucia Guo (left). Photograph: Harriet Line/PA

Guo has been on day trips with him to the G7 in France before, but this is her first extended exposure to public life, and perhaps her first experience of Mail Online full-colour spreads.

Hunt knows, faced by a likely opponent in Boris Johnson whose only known virtue is his personality, he has to be more than the cold-blooded, sometimes awkward, technocrat. His trace of a smile and wide eyes is not enough.

Play Video 0:50 Jeremy Hunt's latest gaffe: Slovenia was 'Soviet vassal state' – video

Guo not only lends some unaffected charisma to his stiffness but some informality, joking about being kept awake for hours at 2am by the amplified Ethiopian Christian chanting in a church just outside the grounds of the commissioner’s residence in Addis Ababa. Hunt says of his wife: “She does a great job in keeping me relaxed in a very intense week and she is also a great diplomatic asset.”

I suggest that the qualities that have made Hunt one of the great survivors of the Cameron era – he appears calm, thoughtful, well-read and well-off – seem out of step with our angry populist times.

He looks taken aback, points out that the Foreign Office is about alliances, not bravado, and then adds: “It was only in 2015 when David Cameron – who is someone to whom many of those words could have been used – managed to get a majority and he deserved it. He delivered better public services, he turned around the British economy despite the worst financial crisis since the war. It is about delivering.”

He insists Brexit has clouded the way people view the Conservative party. “Yes, we are determined to deliver Brexit, but when I was health secretary we announced an extra £200bn for the health service – one of the single biggest increases in funding for a public service in our history – so this is a Conservative party that is firmly rooted in the centre ground.

“People are angry and bored by Brexit,” he says. “They want politicians who listen and people are very suspicious of politicians who appear detached.”

Facebook Twitter Pinterest Hunt holds talks with the Ethiopian electoral board. Photograph: Harriet Line/PA

An ability to engage is one of his qualities. At a roundtable on climate change held in the sweltering botanic gardens in Abuja, he looks his interlocutors in the eye and carefully notes down points in a small notebook. His questions are very direct – about data on desertification in western Sahel, or disputes between pastors and cattle-herders – and at the end he puts the notebook away, and says “well, you have given me marching orders”.

The son of a deputy sea lord, there is something mildly military about his bearing. Hunt’s admonition of the damaging culture of cabinet leaks feels genuine: “Total honesty in private and total loyalty in public.”

He also has an ordered mind, thinking in each department what added value the cabinet minister can bring. In health he recalls the issue over three years was patient safety, something he regarded as a Trojan horse for addressing other perceived ills in the NHS, and the issue to which he would like to return on a more global scale when he retires from politics.

In the Foreign Office, he has developed the themes of media freedom and the persecution of Christians. He is himself an Anglican, but asked if he prays, says it is a private matter. He has been criticised for adopting small bore issues, but disagrees and says the Foreign Office has a facility in raising neglected issues that resonate, whether sexual violence, modern slavery or media freedom.

In the conference hall of the gleaming Chinese-built African Union headquarters in Addis Ababa, he addressed a large day-long event on media freedom.

Facebook Twitter Pinterest Hunt makes a speech at the African Union headquarters. Photograph: Harriet Line/PA

His theme was that true political stability came not from the barrel of the gun, but the freedom of the pen and the integrity of the ballot box. The content of the speech was strong, but there was no effort to warm up his mainly African audience. At its end, in a brief Q&A, he was immediately challenged why – if Britain felt so strongly about ending authoritarianism – did it have excellent relations with butchers of media such as Turkey and Egypt. There was applause. He did not flinch, saying it was an excellent question, and adding it was “a huge concern for us that there are more journalists in prison in Turkey than any other country”.

An argument had to be won that true stability came from strong democratic institutions and power being transferred without bloodshed, he said. “Strongman politics in countries such as Sudan and Algeria brings a certain stability for a certain period of time. But when the strongman goes, Lord knows what is going to happen.”

Later, he expands: “I want to make the argument for social development alongside economic development. The two are inextricably linked. By social development I mean development of democratic institutions. In Senegal, power has changed their leader three times, and Ghana, four times. Investing in strong democratic institutions ultimately leads to stability. It is not just the need for dignity for citizens, it leads to stability.

“Britain needs to recast our relationship with Africa. So while aid is a very important part of our commitment to Africa and the 0.7 % commitment, aid is not the central point any more because there is a new Africa that is radically different from the Bob Geldof Live Aid image that many people in the UK have. It is one of thrusting entrepreneurs, tech parks, huge investment in cities and massive skyscrapers, and we have got to be part of that story.

“Every single African leader I met was worried about how they were going to find the jobs for young people because of this tremendous bulge in numbers. By 2040, one in 10 children born will be born in Nigeria.

“These leaders look to the UK and say ‘you have got the city of London, one of the most business friendly cultures in the world and an unenviable economic record in creating jobs’. We need to change the way we help.”