"We had to stay in the Sheraton next to Heathrow but when we arrived it was about 11 o'clock in the evening and the middle of the winter. It was impossible to train outside.

"I started to think about how I could train and then I noticed that my hotel corridor was very long. I put on my shoes and started to run up and down it, and then some of my friends joined me.

"By that time it was close to midnight and people started to come out of their rooms to look at us. Do you know what happened? They all thought it was an emergency and started following us. One old woman was shouting and running down the corridor in her pyjamas."

The memory brings forth a loud guffaw before Gebrselassie's eyes narrow and he gets to the moral of his story.

"The reason I'm telling you this is that I didn't want to miss a day's training. I always tell young athletes the same thing, 'Wherever you go, whatever you do, what must your top priority be? Running'.

"In my life I do a lot of things but I never forget my training. Athletics is in my blood. The top priority must always be training, training. This is a discipline. You have to do it."

It is a philosophy that defines the 5ft 5in African who, like Usain Bolt in Beijing, took athletics into a new age of boundless possibility by winning the Berlin Marathon in September in 2hrs 3min 59sec –27 seconds inside his own previous world record.

What is all more remarkable is that he achieved it at the age of 35 while juggling athletics with his competing life as the owner of a growing property development company with assets that include commercial buildings across Ethiopia, a cinema, a soon-to-be-opened 120-bedroom hotel (he's toying with the idea of naming it 'Haile Hotel' to make it easy to find on the internet) and plans to build a complex of upmarket apartments and villas.

Oh, and he has also just a signed an exclusive deal to import Hyundai vehicles into Ethiopia. He already sells Isuzu trucks.

How does he do it? That word discipline. His daily routine begins with a 5.30am run of anything up to 30km on the high-altitude trails above Addis Ababa followed by a full day's work at the office, then another training session before returning home at 8pm just in time, if he is lucky, to kiss his four young children goodnight.

It is a treadmill that never stops. His only concession to rest is that on Sundays he has one training session, not two.

"Sometimes my life looks as if it's too much," he admits. "You're training in the morning, going to your office and doing a lot of work. It looks too much, but I've no choice and I accept that. Running is always my top priority. I'm a runner first before anything else. Everything that I have now is because of running."

We are now sitting in the garden of his home in Addis, where the fruits of his labour are manifest in a three-storey mansion built four years ago in mock-Palladian style that would be the envy of many a Premiership footballer. On one side is the family swimming pool, on the other a panoramic view of the city.

Inside, there are two giant, floor-to-ceiling glass cabinets stuffed with hundreds of medals and trophies from a 16-year international career – so many that his wife, Alem, has had to devise a complex indexing system just to keep track of them.

The only ones missing are the Olympic 10,000 metres gold medals he won in Atlanta and Sydney. He gave them to his local church to display in its museum.

He is immensely wealthy by Ethiopian standards, a fact brought home by the humble shacks just a stroll from his house, but he has made it a point of principle to invest his money in his home country.

"Why am I investing all my money here? Because this is my home town," he says. "Of course I have the opportunity to invest my money in Europe or America or wherever, but why not here?"

Not everything he does is motivated by profit. He has built and runs two schools attended by around 2,000 pupils. One of them is in his birthplace of Assela, in southern Ethiopia, where his life of running began, pounding out the 10km from home to school and the 10km back again with a stack of books wedged under his arm.

His passion for education extends to sport and he is currently mentoring 14 young athletes from developing countries as part of a project called G4S 4teen organised by the G4S security company. One of them, 20-year-old Kenyan runner Pauline Korikwiang, was in town last week to learn from the master.

As for his own racing plans, he will be competing next month in the Dubai Marathon, a race he won last year and which could do wonders for his cash flow. A world record will earn a $1 million bonus and Gebrselassie has every intention of going after it.

While he puts his own physical limit at around two hours, three minutes, he is in no doubt that the ultimate barrier, a marathon in under two hours, will one day be breached.

"Believe me, in the future someone will run under two hours. This is not just about the strength of the athlete but the technology.

"When Abebe Bikila won in Rome in 1960, he won in two hours, 15 minutes and something, and that was a world record. After 48 years, Haile Gebrselassie runs more than 10 minutes faster, but what do you expect after 48 years? I believe that in just 20 years' time someone will run under two hours."

The one blot, or rather three blots, on his marathon record are his three defeats in London, including the 2007 race when he pulled out after 18 miles with breathing difficulties.

His doctor put it down to hay fever, which means London in pollen-heavy April is now off limits, though there is one race in the capital that is definitely in his sights.

"The marathon in 2012 will be in August, which will be perfect for me," he says.

He will be 39 by then, but you wouldn't put it past him adding another Olympic gold medal to the display in his church museum. Haile Gebrselassie has no intention of slowing down.