I spent five years during the Angolan Civil War working with colleagues to keep a quarter of a million war displaced people alive across the central highlands of that country.

Our work had no impact whatsoever on the underlying causes of those people’s displacement. The cause was the war which arose from a complex mix of a legacy of the trans-Atlantic slave trade, Cold War geo-politics, regional rivalries, and local personalities, not least the extraordinary psychosis of Jonas Savimbi, the leader of the Angolan rebels. But while we could never have claimed to have contributed to bringing peace what we did ensured that more people survived the violence into its messy and corrupt aftermath in one of Africa’s most beautiful countries.

This is true for every war-related humanitarian emergency. The refugee crisis in the Mediterranean arises from similarly complex causes including the geo-politics of oil, a stupid and illegal invasion of Iraq, regional rivalries between Shia and Sunni, and the bitter lunacy of the DAESH partisans.

The resolution of this violence may take decades. Those involved in humanitarian response will merely try to stanch the bleeding, literally and figuratively, until some settlement can be reached which will end the civilian population displacements.

That is the truth of it in my experience: that effective responses to humanitarian crises must have immediate, medium and long term aspects addressing both the symptoms and causes of the crisis. It is also something that David Cameron should understand from the UK’s engagement with diverse emergency responses during his premiership.

And yet his statement on the 2 Sept did not put me in mind of a statesman wrestling with the complexities of a multi-national humanitarian disaster. Rather I was reminded of an observation, I think by Milan Kundera, that novelists tell the truth with lies and politicians tell lies with the truth. Cameron’s glib comment that, “I don’t think there is an answer that can be achieved simply by taking more and more refugees,” struck me as a stark example of Kundera’s insight.

Of course taking in refugees would no more solve the crisis in the Mediterranean than digging latrines in the displaced camps of Angola brought peace to that country. Giving refuge to desperate human beings has never and could never solve any underlying problem that has caused any war that has forced any population displacement anywhere in the world. That is not its purpose.

The purpose of giving asylum is to preserve people’s lives until the protracted process of ending war can be achieved and some measure of security established to allow civilians to return home. That should be something we understand as Europeans with our collective memory of the convulsions of the Second World War. Without such basic humanitarian measures the death toll of war and humanitarian crises would be much higher.

That is something that David Cameron should also know from that historical perspective as well as the humanitarian one. If he does not know this by now he should not be Prime Minister.

The proximity of the bloodshed of the Mediterranean to Europe imposes different responsibilities on the nations of Europe that are unlike our responsibilities in crises in other parts of the world. No amount of disingeniuity on the part of David Cameron or his fellow travellers changes that. The immediate challenges of this crisis require establishment of safe migration routes into Europe, a fair sharing of the responsibility for resettlement of refugees across the nations of Europe, and, as Germany has already done, suspension of the Dublin Agreement.

If Cameron and the UK government do not face up to the immediate term necessities of this refugee crisis then he may continue to congratulate himself on his clever manipulation of the facts and smooth media obfuscations. But history will be much more clear sighted. Its verdict, on his failure of moral courage at this moment of truth, will be damning.