It’s a considerable achievement that the Sustainable Development Goals now contain an explicit reference to slavery, forced and child labour.

The absence of this issue from the Millennium Development Goals was a travesty, and the consequences of that are highlighted by the number 5.5 million. 5.5 million is the ILO’s most recent estimate, made in 2012, of the number of children in slavery. It is the same as the ILO’s estimate of the number of children in slavery in 2005

In other words, in spite of all the real progress on poverty reduction and development, including a huge fall in the overall numbers of child labourers, during this period international development has completely passed by the millions of children and, for that matter, the tens of millions more adults in slavery across the world.

So the inclusion of slavery eradication in the Sustainable Development Goals is therefore highly significant. It is a recognition by the international community that it has until now comprehensively ignored some of the people in greatest poverty across the globe. But for this recognition to have practical meaning, it must be translated from a sentence in a United Nations pronouncement to a strategy that puts power into the hands of the excluded.

Because one thing that the struggle against slavery puts into the sharpest of focus is that poverty is not merely about a lack of things, but more fundamentally about a lack of power. This remains true in spite of some of the more recent philanthropic discourses on poverty which treat it not even as an economic issue but a technocratic one.

Slavery is one of the most political of development and poverty issues. Those who are enslaved are drawn from communities which are systematically excluded from power to enable their control by those who are more privileged. They include Dalits and Adivasi in South Asia, migrants in Europe, the Middle East, the Americas, South East Asia and West Africa, and children everywhere, .

Prejudice and discrimination against certain groups on arbitrary bases such as caste, ethnicity, gender and religion is still frequently used as a basis upon which the more powerful exclude the more vulnerable from the processes of development. By doing so those same mechanisms of social exclusion also render those discriminated against more vulnerable to slavery.

Development and humanitarian practitioners have barely even been aware of these dynamics and so have failed to address them. If those who call ourselves anti-slavery activists also ignore the fundamentally political nature of these challenges then we too will fail in the imperatives placed upon us by our mandates.

So this is where it gets difficult.

The majority of the underlying causes of slavery are profoundly political and fraught with contention by vested interests which are quite happy with the way the world currently is. Many new entrants to the struggle against slavery are content to see this struggle as merely a matter of locking up evil people by decent police. They are unconcerned with the altogether more contentious questions that underpin the reality of contemporary slavery, such as state-acquiescence in caste-based discrimination, the toleration of child marriage, undermining of rule of national and international law, the failure to establish safe migration routes for vulnerable workers seeking decent work, or the decriminalised international trade in slavery produced goods and services.

For example if the international community is serious in its efforts against slavery how can we continue to acquiesce in the ready access to international markets and warm inclusion to the international polity of Uzbekistan and Qatar, to name but two states, which, with differing degrees of cynicism, have effectively legalised slavery in within their borders.

Or, in spite of its recent casting of itself as a global leader against slavery it is unlikely that the UK has for a moment considered the potential impact that its naked disdain for the European Court of Human Rights will have on the rule of international law in general and as it relates to slavery in particular: that court has been vital since 2000 in forcing governments across Europe, including the UK, to properly respect the rights of victims of slavery. Any credible international struggle against slavery must therefore confront the British government on this, one of their most cherished political prejudices.

And, another political issue: should India be made a permanent member of the UN Security Council while its toleration of caste-based violence is so high, and its efforts to end slavery are so paltry?

So to advance Target 8.7 requires a new concentration of effort that draws in not only traditional ILO partners but also the entire development and humanitarian sector on this issue, recognising that tackling slavery is a fundamental political and development issue and one that is not solely the preserve of law enforcement professionals. Frequently, such as in the brick kilns and quarries of South Asia, it is openly practiced. Therefore there should be a requirement of every credible development and humanitarian agency to consider if they could contribute towards the reduction of slavery and child labour within every community with which they work. This may not always be possible. But asking the question, and considering carefully the dynamics of power and discrimination could lead to empowerment of some who would previously have been overlooked.

Second, there should be much more conscious focus by in development and humanitarian programmes on diminishing the vulnerability to slavery of those communities. For example, ensuring that the children, particularly the daughters, of brick kiln workers and manual scavengers in South Asia have access to proper education, could help break the transmission of slavery across generations. And ensuring that the curriculum promotes human rights, in particular those of girls, and toleration for all would help erode the prejudices that permit human beings to enslave and exploit others.

Aid programmes must work to advance the rule of law by building the capacity of the courts and law enforcement agencies, so that anti-slavery laws can be upheld rather than regarded as mere suggestions to the elites who continue to be able to exploit people with impunity.

Beyond the development and humanitarian sectors the issue of slavery must become a centrepiece of diplomacy, trade and migration policy. In particular there is a need for a clear recognition of the brutal reality that tied visas are de facto licences for trafficking across the world.

This Alliance is vital if we are to obtain progress on Target 8.7. But to do so we must tackle this issue directly, holding each other to account and not merely tinker at the edges with approaches which never confront many of the most powerful who maintain the systems of slavery.

 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.