By Peter Biles
BBC News, Johannesburg
One of Tony Blair's biggest concerns has been the plight of Africa which he once famously described as a scar on the conscience of the world.
The Africa Commission Report set out ideas for combating poverty
There is a large yellow book on the top shelf of my bookcase.
It is more than 450 pages in length, and I dip into it from time to time, whenever I need facts and information about Africa.
It is the report that was drawn up by Tony Blair's Commission for Africa, two years ago. On the back cover, there is a photograph of the 17 commissioners - Tony Blair is in the middle of the front row.
On his right-hand side, he is flanked by Gordon Brown and Bob Geldof.
The Africa Commission was full of promise.
The report starts with these words: "African poverty and stagnation is the greatest tragedy of our time. Poverty on such a scale demands a forceful response."
Mr Blair, and those appointed to help him, wanted new ideas and action for a strong and prosperous Africa.
And so, during the course of 2004 and 2005, the prime minister set about the task of trying to galvanise the rest of the world.
Appropriately, the process began in Addis Ababa - the continent's diplomatic capital - where Emperor Haile Selassie and some of Africa's founding fathers created the Organisation of African Unity, back in 1963.
Mr Blair spent time with villagers in Debre Zeit near Addis Ababa
Mr Blair arrived there on a soaking wet October day, two and a half years ago, and was immediately taken by road to see a small project supporting orphaned children at Debre Zeit - an hour's drive from Addis.
He was invited to sit on the grass in a field, encircled by the children who had come to entertain him with a traditional Ethiopian song.
This was the prime minister rolling up his sleeves and getting a rare chance to find out what life is like in Africa's most deprived communities.
He met an HIV-positive mother, who had been facing near-certain death.
But the woman told Mr Blair how she had been given help, was now running a business and supporting her family.
This, said Mr Blair, was what Africans needed - not just a hand-out of aid, but a helping hand to allow them to help themselves.
The Blair visit to Ethiopia was all too brief.
I wished he could have seen so much more - for this is a nation that epitomises so many of Africa's problems: extreme poverty, rapid population growth, abuses of human rights...
And of course, Ethiopia - with its dramatic landscape - is a country that lies in a rough neighbourhood - the conflict-prone Horn of Africa.
It was Bob Geldof who helped to put Ethiopia on the map two decades ago.
So much has changed since the war-driven famine of 1984, but some things remain the same.
In some Ethiopian villages time appears to have stood still
And so, if he had stayed longer, I would have wanted Tony Blair to have taken the road that leads up the slopes of Entoto Mountain on the northern side of Addis Ababa.
Here, the 4x4s and the battered old Addis taxis jostle for space with herds of goats and donkeys.
But what you also see are women and young girls hunched over as they carry back-breaking loads of firewood from the eucalyptus trees on the mountainside.
On foot, it is a long and arduous trek down into the city.
And it is a medieval image - completely at odds with Tony Blair's vision of a modern, reformed Africa.
It always serves as a reminder to me that it is going to take more than a few promises from the leaders of the Group of Eight industrialised nations to change the way of life here.
I have never doubted Tony Blair's sincerity and commitment to Africa, but there is no question that he took on a gargantuan task when he sought to forge a new partnership between Africa and the developed world.
Africa is full of surprises that can always throw a spanner or two in the works.
The gap between Blair and Meles indicated a strained relationship
The last time I saw the prime minister in this part of the world was at what was described as "a progressive governance summit", a small meeting of like-minded centre-left leaders who had gathered at an incongruous location - a small South African game park, north of Pretoria.
At the news conference afterwards, Tony Blair was joined by - among others - the presidents of South Africa and Brazil.
But Mr Blair had the misfortune - at the time - to find himself sitting next to Ethiopian Prime Minister Meles Zenawi, his erstwhile friend and member of the Commission for Africa.
Only, Prime Minister Meles had - during 2005 - locked up members of the Ethiopian opposition after unrest following disputed elections.
Another blow perhaps, to the "African Renaissance"?
The body language between Blair and Meles, and the rather noticeable gap between their chairs at the news conference seemed to reveal a strained relationship.
So now - in all likelihood - it is Gordon Brown who will take on some of the responsibility of keeping Africa on the world agenda.
He has already done his fair share of cajoling at international finance ministers' meetings. And he has had some hands-on experience of the challenges in Kenya, Tanzania and Mozambique.
But he may want to consider the words of one activist I spoke to this week, who said: "The battle against poverty is a marathon, not a sprint."
From Our Own Correspondent was broadcast on Thursday, 9 May, 2007 at 1100 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.