Almost four decades after being expelled, as part of the consortium that owned the Iraq Petroleum Company, BP is back in Iraq. The oil major that started life as the Anglo-Persian Oil Company a century ago is looking again to the Middle East, home to about two-thirds of the world’s proven oil resources. It is a gamble.

There are still clouds of suspicion, in Iraq and the region, that the US-led invasion was about oil. The Iraqi government – now more sovereign after the withdrawal on Tuesday of US troops from towns and cities – has signally failed to forge consensus around a legal framework for the oil industry and for sharing its revenues.