The Supplementary Convention on the Abolition of Slavery, the Slave Trade, and Institutions and Practices Similar to Slavery was concluded at the European Office of the United Nations in Geneva on 7 September 1956, the Chinese, English, French, Russian and Spanish texts being equally authentic. The Conference of Plenipotentiaries, convened by ECOSOC resolution 608 (XXI), adopted the text on 4 September and opened it for signature; the register date is the conclusion. Article 13: entry into force when two States have become Parties — 30 April 1957 (the USSR and the United Kingdom). Depositary: the UN Secretary-General. It is not the still-operative 1926 Slavery Convention, nor the 1930 ILO Forced Labour Convention.

The preamble recalls the Charter and the Universal Declaration: no one shall be held in slavery. Article 1 requires the progressive, as soon as possible, abolition of debt bondage, serfdom, servile marriage and the delivery of a minor for exploitation — legal definitions, without an operational catalogue. Article 2: suitable minimum ages of marriage, freely expressed consent and registration of marriages, where appropriate.

Article 3 makes the conveyance of slaves from one country to another a criminal offence and requires measures so that flags, ports and airfields are not used for that traffic; Parties exchange information on cases — a framework, without pursuit procedures. Article 4: a slave who takes refuge on board a vessel of a Party is ipso facto free. Articles 5–6 criminalise the marking of persons of servile status and the enslavement of another person. Article 9: no reservations.

Article 11: open for signature until 1 July 1957, then for accession. Article 12: application to non-metropolitan territories. Article 14: denunciation on six months’ notice before the end of a three-year period. The text consulted is UNTS 3822, not the register status page.

The president of the Conference was Emilio Calderón Puig. The Convention augments, and does not replace, the 1926 instrument.

Cover: Palais des Nations in Geneva, the UN European Office at the date of the Conference; we do not claim the hall. Wikimedia Commons, free licence.

Sources consulted: Supplementary Convention on the Abolition of Slavery; UNTS 3822 Supplementary Convention on the Abolition of Slavery.