The movement to abolish slave trade started in Britain with the formation of Anti-slavery movement. The British government abolished the slave trade through anti slave laws (Legislation), treaties and use of force.
The Anti – slavery movement was led by Granville sharp, other members were Thomas Clarkson, William Wilberforce and others.
The first step was taken in 1772 when slavery was declared illegal and abolished in Britain. The humanitarians secured judgment against slavery from the British court.
In 1807, British parliament outlawed slave trade for British subjects.
1817 British negotiated the “reciprocal search treaties” with Spain and Portugal.
Equipment treaties signed with Spain 1835 Portugal 1842 and America 1862.
In E. Africa in 1822 Moresby treaty was signed between Captain Moresby and Sultan Seyyid Said it forbade the shipping of slaves outside the sultan’s territories. British ships were authorized to stop and search suspected Arab slave-carrying dhows.
In 1845, Hamerton treaty was signed between Colonel Hamerton and Sultan Seyyid Said. It forbade the shipping of slaves outside the Sultan‘s East African possessions, i.e, beyond Brava to the north.
In 1871 the British set up a parliamentary commission of inquiry to investigate and report on slave trade in E. Africa.
In 1872 Sir Bartle Frere persuaded Sultan Barghash to stop slave trade but not much was achieved.
On 5th March 1873, the Sultan passed a decree prohibiting the export of slaves from main land and closing of slave market at Zanzibar. Zanzibar slave market was to be closed within 24 hours.
1876 the Sultan decreed that no slaves were to be transported overland.
1897 decree left slaves to claim their freedom themselves
1907 ,slavery was abolished entirely in Zanzibar and Pemba.
In 1927, slavery ended in Tanganyika when Britain took over from Germany after the 2nd world war.