[This is an excerpt from the Memorial 2007 lecture delivered at Senate House, University of London, on 2 October 2025 and shared with The Round Table: The Commonwealth Journal of International Affairs and Policy Studies.]

What results when international criminal law’s pre-eminent institution, the International Criminal Court, hesitantly recognises the breadth of slavery crimes and, most detrimentally, ignores explicit redress for the crime of the slave trade? The answer is impunity.

Moreover, national criminal codes rarely contain provisions for the slave trade. The Netherlands and Lichtenstein are among the European exceptions. The United Kingdom recognised offence does not contain a provision expressly criminalising the slave trade.Footnote39 What has caused the erasure? One word: trafficking. Trafficking in persons, a national crime, at times with cross-border crimes, has diverted legal attention and redress from the contemporary commission of the international crimes of slavery and the slave trade.

Trafficking is a transnational crime found in many national penal codes. Trafficking is often placed under a non-legal term of Modern Slavery. Trafficking presents a legal and, I would argue, a psychological quandary. Trafficking Conventions were drafted first in the early 20th century – in 1904 and 1910.Footnote40 These international instruments were originally called the ‘White Slavery Conventions’, precisely because they applied to white women and girls who were transported across international boarders, actually slave traded, for morally illicit, sexual purposes. The protection offered by the conventions later expanded to all women and all children, in the 1920s and the 1950s trafficking conventions.Footnote41 Today, safeguards against trafficking in persons are contained in the Palermo Protocol to the United Nations Convention on Organized Crime, which entered into force in 2003Footnote42 and that relies upon state policing and inter-state cooperation, as does the United Kingdom’s Anti-Slavery Act.Footnote43 Neither explicitly prohibits the slave trade as intended under international law.

Conflation and confusion exist between the international crimes of the slave trade and slavery, and the transnational crime of trafficking in persons. The origins and the intended purposes of the Trafficking Conventions and the Slavery Convention differ, starkly. Trafficking focuses on the coercive reduction of a person to a form of exploitation. A trafficker can claim the consent of an adult victim as a defence against the crime. Slavery and the slave trade abstain from any requirements of force, abuse or deception of exploitation. Unlike trafficking, no requirements of exploitation must occur either during the slave trade or when reduced to slavery. Also, the slave trade or slavery does not differentiate between the age of victims or accede any relevance to consent. Most importantly, slavery crimes are peremptory norms, with no statute of limitation under international law.Footnote44

This legal prioritisation creates a false hierarchy of trafficking over slavery and, more pointedly, over the slave trade. Emphasis by states and advocates on trafficking has caused the erasure of the application of the slave trade under international law and thwarted their placement in national criminal codes. The obliteration is detrimental to contemporary situations of enslavement.

The Anthony Low Commonwealth Lecture
Memorial Lecture to honour Professor J.E. Jayasuriya

I would not hesitate to suggest that ‘slave trade’ are weighted words to pronounce, much less to enumerate in national and international penal codes. The term ‘trafficking’ removes the history of African-diasporic slavery, removes the remembrance of any actions of the state, and points the finger at actors of organised crimes. Trafficking terminology seemingly confirms the severance from past international wrongful acts. Trafficking, while reaching and redressing horrendous conduct – such as occurred in Britain last month (September 2025) – is not a substitute for the prohibitions of the international crimes of slavery or the slave trade. Our psyche retreats, and our muted legal codes and statutes have rendered the slave trade in desuetude.

Notwithstanding, the international crime of the slave trade is re-emerging.

Sierra Leone, supported cross-regionally by many Latin American, African and Caribbean countries, has proposed to the Assembly of State Parties, the governing body of the International Criminal Court, to amend the Rome Statute.Footnote45 The proposed amendment would enumerate provisions for the slave trade as a crime against humanity under Article 7 of the Rome Statute. It would also amend slavery and the slave trade as war crimes, into Article 8 of the Rome Statute. In December 2026, the Assembly of State Parties will vote upon what is now seen as a non-contentious amendment. The United Kingdom, as an Assembly State Party, as of now, has not signalled its support for the amendment. There is advocacy to be done.

Still, the re-emergence of slavery crimes continues. In 2024, as the Special Advisor for Slavery Crimes, I had the honour to develop the Slavery Crimes Policy for the Office of the Prosecutor of the International Criminal Court. It was the first time that an international judicial institution’s prosecution body examined slavery crimes under international law, as contained in its mandate. The Policy acknowledges that there existed institutions, practices and customs of enslavement and the slave trade throughout time and throughout the world. The Policy holds, as a principle, that an incomplete acknowledgement of how slavery and the slave trade operated historically hinders the identification of their contemporary manifestations. Accordingly, the Policy sets forth a practical skills-based investigative approach and offers relevant legal resources and analyses to lawyers aimed at identifying probative evidence of slavery crimes. The pleading of enslavement and sexual slavery charges – and hopefully, soon, slavery and the slave trade charges – before the International Criminal Court merits the concerted attention of a Policy, because contemporary victims and survivors merit redress. The Slavery Crimes Policy is available on the International Criminal Court’s home page.

Lastly, the re-emergence of slavery crimes under international law is exemplified by the General Assembly of the United Nations’ intention to draft a crimes against humanity treaty. The United Nations’ International Law Commission delivered a draft of the treaty to the General Assembly’s Sixth Committee that did not include a provision for the slave trade within crimes against humanity.

Sierra Leone, again, proposed that the slave trade be enumerated in the new treaty. Sierra Leone is joined by other United Nation states, called the Group of Friends, and by a large coalition of civil society.Footnote46 The re-emergence of the slave trade is gaining momentum. The United Kingdom, to date, has not signalled its support for the provision of the slave trade in the new crimes against humanity treaty. There is advocacy yet to be done to restore the prohibition of the slave trade to its rightful place under international law.

This evening, I conclude by urging remembrance and recognition of the slave trade, especially the internal slave trade. I urge that we, as descendants of the historic institutions of slavery and slave trading, stand in solidarity with today’s child soldiers, the women and girls enslaved in forced marriages, enslaved mine workers, enslaved domestic workers, the migrants who are enslaved and slave traded across the deserts of Northern Africa, and the Yazidi population, enslaved and slave traded by the Da’esh militias.

The International Criminal Court and the forthcoming United Nations Crimes Against Humanity Treaty must mandate redress for slave trade and slavery. They represent the blackest of black letter law, permeated by the black blood of Africans and their descendants.

Patricia Viseur Sellers, Law Faculty, University of Oxford, UK.