Opec countries drastically curbed their output in the first month of their new production agreement, in the clearest sign to date that the world’s biggest oil producers are committed to living up to the November pact to cut global supplies. The limits adopted by the oil cartel in January have been “one of the deepest in the history of Opec output cut initiatives”, the International Energy Agency said on Friday. Brent crude, the international benchmark, jumped more than $1 a barrel after the IEA announced its finding, rising to $56.73. Opec has a poor record of meeting targets and does not apply penalties to members who break limits, leading some analysts to question whether the November pact, the cartel’s first production cut in eight years, would be enforced. Opec said it was targeting around 1.2m barrels a day in reductions among members alone. The IEA said Opec crude production fell by 1m b/d to 32.06m b/d in January, surpassing expectations at the start of the six-month supply agreement, helping to ease a global supply glut that caused the most severe price crash in more than a decade.