Opec clinched a deal to curtail oil supply, confounding sceptics as the need to clear a record global crude glut — and prove the group’s credibility — brought its first cuts in eight years.

An informal Opec meeting next month is unlikely to deliver any agreement to limit production because several members including Iran are still pumping below capacity.

Oil gained after Opec’s president said the group will hold informal talks in Algiers next month and predicted the current bear market would be short lived.