It was difficult at times to recall that the military intervention in Iraq being debated in the House of Commons involves sending six Tornadoes to bomb suspected Isis positions. It is very much a symbolic action from the British point of view. MPs seemed to be trying to grapple with the complexity of what is happening but not quite succeeding. Cameron and others made great play with the idea that military action is in support of a new, inclusive Iraqi government, when in fact it is as Shia-dominated as the old. Its most effective military strike force are Iranian-managed Shia militias but they, along with the Iraqi army, terrify the Sunni.

It is reasonable to bomb and give air cover to defend Kurds under attack by Isis, but giving air cover to the Iraqi army, Shia militias or peshmerga advancing into Sunni areas means joining one side in a sectarian civil war. Airstrikes are effective within very strict limits. Isis was a guerrilla organisation and easily reverts to guerrilla tactics, making it next to impossible to detect.

What was lacking in Cameron and Miliband’s speeches was any sense of the necessity of arranging ceasefires among the non-Isis forces in Syria. It is absurd to have a coalition against Isis that largely excludes those actually fighting Isis, such as the Syrian army, Iran, Hizbullah and the Syrian Kurds. Curious also that there was so little mention of Libya, where air intervention, supposedly used on humanitarian grounds, has led to a country torn apart by contending militias. Why did so few MPs even bring up Libya? Understandable why Cameron didn’t.