Read more: Remembering an Irish hero of Haiti

Read more: Irish connections run very deep to Haiti

One year after a devastating earthquake leveled Haiti’s capital, the Iron Market will reopen thanks to one Irish billionaire. The Iron Market is Haiti’s major shopping area.

Denis O’ Brien, founder and CEO of  mobile phone company Digicel, has funded the reconstruction of the market, which will open on January 11 with $12 million in funds.

"It's a celebration, but it's probably the saddest day in the history of Haiti," says Denis O'Brien, the Irish billionaire tycoon who has funded the reconstruction of the Iron Market. "We'll have to get the balance right."

The reconstruction of the Marché en Fer is the only visible sign of building in Port-au-Prince and has taken on major significance for the country, attracting film director Patrick Forbes to make a documentary about the project. "He's a bulldozer of a man," Forbes said of O’Brien to The Guardian. "George Howard, the site manager, calls O'Brien a ball-breaker whom you thank for breaking your balls."

At $12 m, the cost of the reconstruction is only a fraction of the $500bn of aid promised to Haiti, but only $6bn of that has ever been seen. Little of the billions of dollars of aid promised by governments and individuals has arrived, possibly because the corrupted Haitian elite would rather filter the money before it reaches its subjects.

Said Forbes: “When I first went to Haiti, I thought: 'Where are all the JCBs? Where's the rebuilding?' There was none. Only O'Brien's project. Apart from that, just all these guys clearing rocks."

The opening of the market, which was originally set for December 12, 2010, has already been postponed a month by delays, riots over election results and the closure of the airport.

"I think they'll make it," says Forbes. "Just."

When O'Brien announced his intention to rebuild the Iron Market within a year of the earthquake, McAslan, a Glaswegian architect whose firm, McAslan + Partners, has a special emphasis on social and community building, was attracted to the project.

"By mid-February," recalls McAslan, "we had a rag-bag collection of people in various places who were interested and determined to get it done within a year." The sense of urgency was not bombast on O'Brien's part, says McAslan, but "the fact that this was the only major reconstruction in Haiti, and therefore a symbol of hope. We had to proceed against immeasurable odds to keep the project on track."

O'Brien, who made his initial fortune with the sale in 2001 of his Irish mobile-phone network Estat, was estimated by Forbes magazine in 2009 to be worth $2.2bn. He then established Digicel in Jamaica. Before Digicel arrived in Haiti in 2006, only 5% of the population used mobile phones; today 30% own one. With a total investment of more than $300m over the past four years, O'Brien has become the single largest investor in the country.

Named by the mayor of Port-au-Prince as the city's "Goodwill Ambassador" to the world, O’Brien has donated $5m to the Haiti Relief charity and a further $800,000 was raised for Haiti by a "text and donate" appeal to Digicel's mobile-phone customers in other parts of the Caribbean and Central America.

O'Brien claims to love Haiti better than the governing Haitians. "Even if a lot of the Haitian elite don't believe in their country," he told Time magazine, "I do."

Forbes' film, From Haiti's Ashes, will be shown on the BBC.

Read more: Remembering an Irish hero of Haiti

Read more: Irish connections run very deep to Haiti