Reuters/Bogota

Enrique Penalosa, a former mayor of Bogota, would win the presidential election in a second round against President Juan Manuel Santos, according to a poll by Centro Nacional de Consultoria.
The center-left Penalosa, who ran the capital city from 1998 to 2001, would finish 26% to 18% behind Santos in the first ballot on May 25, but beat him in a June runoff with 41% to 36%, the survey of 1,500 people showed.
While Penalosa, a 59-year-old economist, has been rising in recent polls, CNC conducted interviews nationwide via fixed-line telephones, a method that tends to draw answers from wealthier voters and so is not necessarily representative of voter intent as face-to-face interviews or via cellular phones.
The results differ from those of surveys by Gallup and Ipsos Napoleon Franco, which give the centre-right Santos a comfortable win in both rounds of voting against right-wing Oscar Ivan Zuluaga.
The two pollsters tend to conduct face-to-face interviews in households nationwide. A candidate needs more than 50% in the first round to avoid a runoff on June 15.
Penalosa, a contender for the Green Alliance party, is unlikely to cut off peace talks with the Revolutionary Armed Forces of Colombia, a Marxist rebel group known as FARC.  
Santos has staked his legacy on ending the five-decade war which has killed more than 200,000 people, mostly civilians. He launched the talks at the end of 2012.
The Green Alliance has attracted a more independent membership as well as leftist activists from the now-defunct M-19 guerrilla movement.  The poll was conducted between March 25 and 28 in 75 municipalities throughout Colombia. It has a margin of error of 2.5%.
Among the 33mn Colombians eligible to vote, some 14% said they would abstain in the second round, 5% said they would mark the ballot as “none of the above” and 4% were undecided, according to the poll.
Oscar Ivan Zuluaga, who represents the party formed by right-wing ex-president Alvaro Uribe, slipped into third place in the CNC survey of voting intent for the first round. Zuluaga is a fierce critic of talks with the FARC.