But there are other issues at stake. There is, first of all, something profoundly faulty in labour contracting itself, that permits exploitation, and hence trafficking, to take place. As Roger Plant, the head of the Special Action Programme to Combat Forced Labour at the ILO, puts it, it is not a question of a "few rotten apples" but of the systematic, worldwide "coercive exploitation of human beings". States, actively promoting a false image of human trafficking as illegal immigration, effectively draw attention away from the dependence of the West on cheap and malleable workers in the unregulated and unprotected labour market. And this distortion can be attacked only by strong labour laws, vigorously enforced against industries profiting from cheap labour, by clear and fair immigration controls and by generous and far-sighted programmes for the protection and rehabilitation of victims. It is the exploitation of all workers, trafficked or otherwise, Plant argues, rather than the movement of people into situations in which they will be exploited that has to be fought. 

And there is perhaps a more fundamental point to be made as to why the many anti-trafficking measures are having such little effect. To focus, as they do, on trafficking solely as a criminal activity is to ignore the nature of migration itself. People move, and have always moved, in search of work and better lives and they will continue doing so. Yet in a world that is supposed to be more accessible to everyone, the right to migrate remains a privilege offered to the very few. Mechanisms of control and punishment over the mobility of migrants, instead of eliminating trafficking, may actually be creating the conditions in which it will grow and spread, while at the same time diverting attention away from the global inequalities in wealth that drive people to migrate in the first place. Trafficking would not occur, argue the authors of a recent paper on human trafficking in Oxford University's St Antony's International Review, in a world with well-managed migration policies. It is no coincidence that the growth in trafficking has come at a time of increasing demand for cheap labour and ever tighter border controls: desperate people have no alternative but to seek the services of traffickers, hoping that their promises of a better life are genuine.

That people will continue to move from poor countries to rich countries is inevitable, as is the fact that many will be deceived along the way. There are basic movements that defy the neat categories and solutions expressed in protocols and international agreements and no number of laws will curb them. Recognising this vast, messy, unwieldy subject for what it is, and attempting to tackle its causes rather than cynically addressing its symptoms, may be the only way ahead.