Patrick Cockburn: They denied it was about Iraq's resources. But it never rang true

The supposed disinterest expressed by international oil companies in the outcome of the invasion of Iraq in the year before it was launched never quite made sense. Iraqis used to ask ironically if the rest of the world would have been quite so interested in the fate of their country if its main export had been cabbages.

Oil companies are intensely interested in what happens in Iraq because it contains some of the world's largest unexploited and under-exploited oilfields. This includes nine "super giants" around Basra each with 5 billion barrels of exploitable crude.

In 2002 many British companies were suspicious that they might be locked out by US oil companies in the event of the US becoming the dominant power in Iraq. This was not a paranoid suspicion; early non-oil contracts awarded by the US-dominated administration in Baghdad in 2003 went to American corporations.

In the event Iraq has held three rounds of bidding for contracts to manage and develop Iraqi oilfields since 2008. BP along with China's CNPC is heavily involved in Iraq's largest oilfield, Rumaila, in the far south on the Kuwaiti border. Royal Dutch Shell with Petronas of Malaysia has the contract for the Majnoon field on the border with Iran. Exxonmobil and Royal Dutch Shell are developing West Qurna 1.

It has never seemed likely that the US and Britain invaded Iraq primarily for its oil. Reasserting US self-confidence as a super-power after 9/11 was surely a greater motive. The UK went along with this in order to remain America's chief ally. Both President Bush and Tony Blair thought the war would be easy.

But would they have gone to war if Iraq had been producing cabbages? Probably not.