Ollanta Humala, 42, a former army officer, was predicted to secure 29.2% of the vote ahead of his nearest rival, Lourdes Flores, a conservative pro-business former congresswoman, on 25.6%, and Alan Garcia, the former centre-left president, on 21.9%, according to a poll by Lima University.

The two highest placed candidates will go into a run-off, but analysts said that Humala would find it hard to defeat either of his two rivals.

Humala, who likes to be known as “El Comandante”, has targeted the 14m Peruvians living on or below the poverty line who have seen little benefits from the free-market reforms and economic liberalisation of the 1990s.

Suspicious of foreign investment, he has pledged to review all contracts with privatised companies and called for obligatory state participation in “strategic” assets including ports, airports, mines and the energy sector. He has also said that he will block a proposed free-trade agreement with Washington.

Humala’s anti-Americanism is reminiscent of that of Hugo Chavez, the left-leaning president of Venezuela, and Evo Morales, who was elected leader of Bolivia in December.

During his campaign, Humala has visited both men, who, together with Fidel Castro, the veteran Cuban leader, have jokingly referred to themselves as “the axis of good” — a reference to the characterisation in 2002 of President George W Bush of Iran, North Korea and Saddam Hussein’s Iraq as the axis of evil.

“El Comandante” first came to national prominence in 2000 when, as a lieutenant-colonel in the army, he mounted a small uprising against Alberto Fujimori, the then president. It was a dismal failure but left Humala with a romantic popular image.

The swell of support for Humala will add to concerns in Washington about the apparent swing to the left in Latin America, a region it considers its backyard.

It coincides with a further deterioration in US relations with Venezuela after the car of William Brownfield, the ambassador, was pelted with eggs, onions and tomatoes by supporters of Chavez during a visit to a housing estate in Caracas, the capital. The State Department protested.

The Venezuelan leader has long been at loggerheads with Washington, accusing it of orchestrating assassination and coup attempts in order to get its hands on his country’s vast oil reserves.

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