Anti-Slavery International is the world''s oldest international human rights organisation. Its roots stretch back to 1787 when the first abolitionist society was formed. This broad-based society was at the forefront of the movements to abolish the slave trade (achieved in Britain in 1807) as well as slavery throughout the British colonies (achieved in 1833).

But abolition did not mean instant freedom for slaves. Instead, they had to continue serving the same masters under a system many considered an alternative form of slavery: ''apprenticeship''. This lasted between six and 12 years, during which many were severely beaten. Growing public pressure led Parliament to abolish apprenticeships on 1 August 1838, three years before the date set by the Emancipation Act. This early example of a non-governmental organisation demonstrated the power of popular pressure for political change.

A year later the abolition campaign was expanded and the British and Foreign Anti-Slavery Society was formed on 17 April 1839, declaring its commitment to abolishing slavery throughout the world. This organisation continues today under the name Anti-Slavery International. The organisation''s early leaders included Sir Thomas Fowell Buxton, Thomas Clarkson, and other notable Quakers, Baptists, and Methodists.

By the 1890s the Society''s mandate included working to stop the ill treatment of indigenous peoples, leading it in 1909 to merge with the Aborigines'' Protection Society.

The Anti-Slavery and Aborigines'' Protection Society played a key role in campaigning for and drafting the 1926 Convention on the Abolition of Slavery and the 1956 Supplementary Convention on the Abolition of Slavery, the Slave Trade and Institutions and Practices Similar to Slavery. In 1975, it worked for the creation of a group of experts within the United Nations dedicated to the elimination of slavery, now called the UN Working Group on Contemporary Forms of Slavery.

In 1990 the Society changed its name to Anti-Slavery International, sometimes known as Anti-Slavery. Its main areas of work currently include forced and bonded labour, the worst forms of child labour, trafficking of human beings, and traditional or ''chattel'' slavery.