Why, hundreds of years after it was legally abolished, does slavery persist? The last episode of Slavery: A 21st Century Evil is a televised debate in which this question, among others, was posed to a panel of those who direct or seek to influence government policies on slavery across the world.

The debate was held at Decatur House on Washington's Lafayette Square - the site of the only remaining physical evidence that African Americans were once held in bondage within sight of the White House - as an iconic venue for the debate on a trade that refuses to die.

Moderator Rageh Omaar was joined by: Luis C d'Baca from the US State Department Office to Monitor and Combat Trafficking in Persons; Kevin Bales, the president of Free the Slaves; David Batstone, the president of Not for Sale; and Joy Ezeilo, the UN Special Rapporteur on Trafficking in Persons.

The debate first aired on Thursday, November 24, at at 2000 GMT.