His trek had only become possible in recent years because of relative political stability in Sudan. "The one thing I did come away with was a sense of hope," he said.
"People were desperately trying to get themselves out of poverty. I also saw how incredibly hospitable they were to a man walking through Africa."
His trek began in Rwanda in December 2013 and he took an estimated 7 million steps before reaching the end of his trip in September. He said terrain and weather had been the hardest parts of his journey, which had ranged over mountains, savannah and the Sahara.
The darkest moment for his expedition was when Matthew Power, a 39-year-old American journalist accompanying him for several days, had collapsed and died of heat exhaustion in Uganda in March.
Wood said: "We had this terrible tragedy along the way. It really brought home the reality of the risks involved in undertaking a journey like that."
His choice of route along the banks of the Nile meant he and the local guides and interpreters who travelled with him often faced the dangers of local wildlife.
He said: "Walking through a national park we got charged by a hippo. My guides had told me that the most dangerous place in Africa is between a hippo and the water."
In March he was caught up in fighting in South Sudan when militiamen attacked a United Nations compound while he was in the town of Bor. He was caught up in a firefight as gunfire swept through the town and several refugees were shot dead and wounded.
Wood, who served in The Parachute Regiment, said: "It was a pretty hairy moment. It's one thing dealing with that sort of thing when you are in the Army, but another when you are there without backup."
He now hopes to undertake another expedition this year.
