Early in the struggle to abolish the British slave trade, the leading abolitionists realized that to make any abolition effective it would have to be universal. Another reason for seeking foreign co-operation was to undermine the domestic opposition argument that Britain's maritime rivals would be the chief beneficiaries of a British abolition. In December 1787 the Prime Minister, William Pitt, himself an advocate of abolition, wrote to William Eden, then Minister in Paris and Minister-designate to Madrid, referring to the abolitionist crusade, ‘if you see any chance of success in France, I hope you will lay your ground as soon as possible with a view to Spain also’.

The Parliamentary leader of the abolitionists, William Wilberforce, initiated several other attempts to obtain international agreement on the prohibition of the slave trade during the next twenty years, but the French Revolution, the revolution in St Domingue and the Napoleonic Wars dashed any hopes of success just as they acted to frustrate the abolitionist campaign within Britain. Wilberforce never lost an opportunity to press for international action, especially prior to the peace negotiations leading to the Treaty of Amiens in 1802, but the failure of these tentative overtures accentuated the importance of the struggle in Britain. British abolitionists were morally certain other nations would follow Britain's lead if only Britain would set the example. Henry Brougham confessed:

We have been the chief traders, I mean, the ringleaders in the crime.