Maracaibo, Venezuela: Soaked by rain and perspiration, Henrique Capriles retreated reluctantly inside his campaign bus as the horn-blowing, flag-waving convoy crept through the potholed slums of Maracaibo, Venezuela’s second city.

A late-evening tropical thunderstorm had finally forced him from his place atop a pickup truck after a typical 12-hour day of rapturous rallies and rock-star receptions for the dashing 40-year-old opposition leader.

Undeterred by the downpour, crowds chanted his name as firecrackers erupted in pitch-darkness that is testimony to the failure of the country with the world’s largest oil reserves to deliver electricity to its own poor.

In presidential elections on Sunday, Capriles faces one of the toughest challenges in global politics: defeating Hugo Chavez.

The autocratic socialist president dominates the airwaves and has tapped into the state’s deep oil coffers to fund his campaign and “buy” votes with a calculated explosion of investment in social programmes in the weeks before the vote.

But, despite its energy riches, Venezuela is mired in debt and unemployment as state-imposed oil price and exchange rate controls shackle the economy. And violent crime is so endemic that Caracas has the unenviable title of murder capital of the world.

Most serious competition

Now, with the long-divided opposition united behind a charismatic state governor who is already a veteran of Venezuela’s rough-and-tumble politics despite his youth, President Chavez is facing his most serious competition at the ballot box since he came to power in 1998. At stake is the grip on power of an anti-western firebrand who embraces Iran and China and is seeking to use the nation’s oil wealth to export his dream of a socialist revolution across Latin America.

It is a “David and Goliath” battle, Capriles told the Sunday Telegraph during an interview in which he pledged radical breaks from the policies of the former paratrooper known to his fervent supporters as “El Comandante”.

On his first day in office, he said, he would halt the “gifts” of free or heavily subsidised oil to Chavez’s Left-wing ideological allies in Cuba and Nicaragua. And there be no more discount deals for sympathetic western leaders such as Ken Livingstone, a Chavez admirer who as London mayor negotiated cheap oil for the capital’s buses. The cosy relationship with Iran would end and he would review the land expropriations conducted under Chavez’s agrarian reform “fiasco” — which included the seizure of estates from the Britain’s Vestey Group. “We have so many problems here in Venezuela but Chavez’s priority is to create his own world revolution,” Capriles said. “His land reform programme has been a disaster and he sends billions of dollars of oil abroad each year, but there are hundreds of thousands of Venezuelans who have problems putting food on the table. “For Chavez, that is not important. What matters to him is building what he calls his 21st-century socialism.”

Capriles is an experienced political campaigner. At just 26, he became the youngest Venezuelan MP ever elected, later serving as vice-president of the national deputy of chambers. He held a major Caracas mayoralty for eight years and defeated a Chavez ally in 2008 to win the governorship of Miranda, the second most populous state. He was jailed briefly in 2004 for his alleged involvement in a short-lived coup against Chavez in 2002, a conviction that supporters insist was a politically motivated set-up. He is the scion of one of the country’s richest business families.

The great-grandson of Jewish victims of the Nazis’ Treblinka extermination camp, he is himself a devout Catholic. The Sunday Telegraph spent a day on the campaign trail with Capriles as he dashed across two states, drawing crowds from the coffee plantations of the Andean foothills to the steamy lowlands around Lake Maracaibo.

Female fans

Until recently, he would walk, thronged by supporters, for several miles each day. But as their numbers have surged, the candidate has been forced to swap feet for wheels and now takes centre stage in a colourful caravan of cars, buses, lorries and motorcycles.

The youthful politician with the broad toothy grin is mobbed, hugged and, indeed, often groped by adoring women at opposition rallies.

Currently single, a status that only adds to his allure to female fans, his previous relationships with two high-profile Venezuelan women were staples for glossy magazines.

He is an enthusiastic marathon runner and a workaholic who sleeps just four hours a night. The energy of his campaign is in contrast to that of Chavez, 58, who was, in his time, regarded as a heart-throb of the Left. The president has undergone debilitating treatments for cancer over the past 15 months in Cuba

Chavez has thrown insults at his opponent, whom he portrays as an “imperialist lackey” intent on selling out Venezuelan oil to international companies. He has accused Capriles of planning a “savage” programme of privatisation and cuts that would benefit the old elite and spark “civil war”.

“He’s afraid,” said Capriles, who insisted that, despite his pro-business roots, his role model is Brazil, which has pursued a social democratic strategy mixing the public and private sectors.

— The Telegraph Group Ltd, London 2012