Shell's beleaguered campaign to produce oil in the Arctic has suffered a further setback after the US Interior Secretary Ken Salazar said the company "screwed up" its attempt to drill in Alaska last year.
Furthermore, he said, Shell will not be allowed to drill in the area again until it demonstrates it can handle Arctic conditions and commissions an independent audit of its management systems.
The US Department of the Interior ordered a 60-day review in January of Shell's plans to drill off the coast of Alaska after a series of incidents in the area involving its ships, rigs and equipment that culminated in the grounding of the Kulluk rig on New Year's Eve.
Releasing the findings of the review, Mr Salazar said: "Shell screwed up in 2012 and we're not going to let them screw up when they try to drill in the Arctic again.
"Shell's difficulties have raised serious questions regarding its ability to operate safely and responsibly in the challenging and unpredictable conditions offshore Alaska."
Shell has now postponed its Arctic drilling until at least next year.