War broke out between Britain and France in 1793. Both feared and threatened invasion from the other. Conflict extended beyond Europe to include the colonies in what was known first as the 'French Revolutionary Wars' then the 'Napoleonic Wars'.
In 1804 Napoleon, Emperor of France, made slavery legal again in the French colonies. Napoleon's efforts to restore slavery meant that the abolitionist campaign would help to undermine Napoleon's plans for the Caribbean.
In 1805 Admiral Lord Nelson attacked and defeated the Napoleonic Navy in the Battle of Trafalgar. By 1806 the Act banning any slave trade between British merchants and foreign colonies was intended to further attack French interests.
The Foreign Slave Trade Abolition Bill of 1806 represented a change of strategy. With the link now broken between pro-abolition and pro-French sympathy in the public mind, the abolitionist campaign revived. The parliamentary abolitionists secretly agreed to pretend to ‘ignore’ a Foreign Slave Trade Abolition Bill, which was instead sold as an anti-French measure to the House of Commons. The Bill was designed to prevent British merchants from importing slaves into the territories of foreign powers.
It was only on the third reading of the Bill, that the pro-slavery lobby realised what was really at stake behind the Bill. It would have been difficult to oppose it because the Government presented it as a way to win the Napoleonic war.
The consequence of the Bill would have been to stop over three-quarters of the existing trade. It would have taken the economic bottom out of the Atlantic slave trade. The path had been cleared for full abolition.