Iran has pledged to begin pumping up to half a million barrels of extra crude per day within one week

Millions of extra barrels of Iranian crude oil could begin spilling on to world markets next week, adding further to fierce downward pressure on prices, experts have warned.

With the United Nations, which completed inspections at an Iranian nuclear site yesterday, expected to approve the removal of trade sanctions as early as Monday, Iran has pledged to begin pumping up to half a million barrels of extra crude per day within one week.

The excess output promises to exacerbate a growing international glut of oil that has already sent prices sinking to their lowest level in 12 years. The price of the benchmark Brent crude contract fell as low as $29.73 early yesterday — the lowest level since February 2004. It later rebounded in New