Sliding oil prices dealt producers another blow yesterday despite new evidence that they have met targeted output cuts in full.

The West's energy think tank, the International Energy Agency (IEA), warned that lasting oil price gains would only come when Asian economies started a recovery and lifted petroleum demand.

London benchmark Brent blend crude futures prices closed 57 cents lower at $13.21 a barrel, calling into question the decision of major producers last week not to pursue a fresh round of supply reductions.