When he was growing up just outside the Ethiopian capital of Addis Ababa – appropriately, a marathon's distance away – Tsegaye Kebede would collect firewood for sale, in order to buy bread and tea for his 13 siblings. The then schoolboy would earn barely £1 a day, none of which he would keep for himself. Later today, he could walk away with a top prize of £33,000.
Last year Kebede pocketed half-a-million dollars for winning the overall World Marathon Majors title, effectively marking him as the world's most consistent marathon runner for the past two years.
Understandably, the defending London Marathon champion, who also won the race in 2010, says: "Running marathons has given me everything. It's amazing. Now my family are living a good life, they have electricity, they have everything, and I'm happy to have given them this chance.
"My running has brought them much happiness. If I didn't run, if I didn't focus on training, I wouldn't have had the chance."
Kebede paints the picture of a happy household when he was growing up. Conditions may have been cramped, the family back then lacked electricity, and he would live off one meal a day, but his ever-present smile barely waned.
"For us, life was very strong for my family," he reflects. "We had nothing, my family, just each other. It was difficult for everybody with no money, no income really at all. After school I would collect wood for my father to sell in Addis."
The one solo outlet for the selfless child was running. Barefoot, he took it up at the age of eight and would rise early each morning to put in his training hours before school. After school he would work, not only collecting firewood but also herding livestock.
"I would just run because I enjoyed it," he says. "I still enjoy it. It's the only way to be."
The diminutive distance runner, at 5ft 2in the smallest man in the elite field, happened to have a talent for it. He entered a 10-kilometre race in Addis, where he was talent-spotted by Geteneh Tessema, married to Gete Wami, Paula Radcliffe's great rival, and a man known in Ethiopia as the "champion maker".
By 2007, Kebede was running his first marathon in the Ethiopian capital. The 27-year-old can still vividly recall that debut, in part down to the harrowing moment in which the bus in which he was travelling flipped on its side as he returned from training in the days leading up to it. He downplays the severity of the incident, saying: "The bus fell down a bit of a cliff. It was a little bit of an accident but not too bad. I was OK."
In comparison, his build-up to attempting a third London win has been remarkably smooth. All week he has looked relaxed to the point of horizontal, and "can think of no reason why I can't win". He adds: "Of course we have this amazing competition, but I'm relaxed. Why not? It helps with your mind, I've done the work. Why don't I win? I just have to enjoy it.
" It's my sixth year, and I know every corner. It's like home, with everyone supporting me when I'm running, and clapping. I'm very familiar with it."
In five appearances, Kebede has only once finished off the podium in the capital – he came fifth in 2011 – and his never-say-die attitude held him in particularly good stead a year ago.
With the field setting an alarming pace early on, he dropped back, by as much as one minute at one point. But his penchant for pulling out the stops in the final stages, as he did with a blistering run for Olympic bronze in 2008, came to the fore as he clawed back the leader, Emmanuel Mutai, for the win.
Such is the topsy-turvy nature of marathon running that Kebede is reluctant to make any predictions about the possible pace. However, he says: "I don't think it will be a world record. That's difficult, as the course is a little difficult, up and down. The course record [2:04.44, set by Wilson Kipsang in 2012] I think is possible if the weather is good."
On the start line today, Kebede says he will be running "hungry", metaphorically at least, in parallel with his upbringing.
"If you're hungry in body and mind you get stronger. If I'm hungry one day and don't eat, I know I will eat the next day. It's the same feeling with running. You can beat everything when it's difficult, like with this field. I feel hungry."