Gustavo Petro. Photo: Internet Source

Petro beat construction magnate Rodolfo Hernandez with an unexpectedly wide margin of some 720,000 votes. The two had been technically tied in polling ahead of the vote.

Petro, a former mayor of capital Bogota and current senator, has pledged to fight inequality with free university education, pension reforms and high taxes on unproductive land. He won 50.5% to Hernandez’s 47.3%.

Petro’s proposals – especially a ban on new oil projects – have startled some investors, though he has promised to respect current contracts.

His victory was likely to cause market jitters until his cabinet is announced, analysts told Reuters on Sunday.

Supporter Alejandro Forero, 40, who uses a wheelchair, cried as results rolled in at the Petro campaign celebration in Bogota.

“Finally, thank God. I know he will be a good president and he will help those of us who are least privileged. This is going to change for the better,” said Forero, who is unemployed.

Some people were dancing in the street near Bogota’s largest polling place, despite ongoing rain.

This campaign was Petro’s third presidential bid and his victory adds the Andean nation to a list of Latin American countries that have elected progressives in recent years.

A fragmented congress, where a dozen parties have seats, will act as a check on Petro’s proposals, said Daniela Cuellar of FTI Consulting.

“Colombia’s institutional strength and rule of law appear sufficiently robust for the country to maintain economic stability,” said Cuellar. “Moreover, campaigning is not governing, Petro’s policies will be more moderate.”

“Even if he tries to pass radical reforms, he does not have the congressional support to implement them,” she added.

Petro, 62, said he was tortured by the military when he was detained for his involvement with the guerrillas, and his potential victory had high-ranking armed forces officials bracing for change.

Petro’s running mate Francia Marquez, a single mother and former housekeeper, will be the country’s first Afro-Colombian woman vice-president.