The Royal Navy established the West Africa Squadron (or Preventative Squadron) at substantial expense in 1808 after Parliament passed the Slave Trade Act of 1807. The squadron's task was to suppress the Atlantic slave trade by patrolling the coast of West Africa. With a home base at Portsmouth, it began with two small ships, the 32-gun fifth-rate frigate HMS Solebay and the Cruizer-class brig-sloop HMS Derwent. At the height of its operations, the squadron employed a sixth of the Royal Navy fleet and marines.
Between 1808 and 1860 the West Africa Squadron captured 1,600 slave ships and freed 150,000 Africans.
On 25 March 1807 Britain formally abolished the Slave Trade, prohibiting British subjects from trading in slaves, crewing slave ships, sponsoring slave ships, or fitting out slave ships. The Act also included a clause allowing the seizure of ships without slave cargoes on board but equipped to trade in slaves. In order to enforce this ruling in 1808 the Admiralty dispatched two vessels to police the African Coast. The small British force was able, due to the ongoing Napoleonic Wars, to stop any ship bearing the flag of an enemy nation, making suppression activities much easier. Portugal, however, was one of the largest slave trading nations and Britain's ally against France. So in February 1810 under diplomatic pressure, it signed a convention that allowed British ships to police Portuguese shipping, meaning Portugal could only trade in slaves from its own African possessions.
Interestingly, the letter of marque Dart, a private vessel chasing slavers to profit from the capture of slave ships and the bounties the British government paid for freed slaves, made the first captures under the 1810 convention. Dart, and in 1813 another letter of marque, (Kitty), were the only two vessels to pursue slavers for profit, and thus augment the efforts of the West Africa Squadron. The lack of private initiatives, and their short duration, suggest that they were not profitable.
With the ending of the Napoleonic Wars Viscount Castlereagh had ensured a declaration against Slavery appeared in the text of the Congress of Vienna, committing all signatories to the eventual abolition of the trade. In 1814 France agreed to cease trading, and Spain in 1817 agreed to cease North of the equator, adding to the mandate of the Squadron. Unfortunately early treaties against slave trading with foreign powers were often very weak and in practice meant only if slaves were found on board at the time of capture could a vessel be prosecuted.
In order to prosecute vessels captured, and thereby allowing the Navy to claim its prizes, a series of courts were established along the African Coast. In 1807 a Vice Admiralty Court was established in Freetown, Sierra Leone. In 1817 several Mixed Commission Courts were established, replacing the Vice Admiralty Court in Freetown. These Mixed Commission Courts had officials from both Britain and foreign powers, with Anglo-Portuguese, Anglo-Spanish, and Anglo-Dutch courts being established in Sierra Leone.
Far from the Pax Britannica style policing of the 1840s and 1850s, early efforts to suppress the Slave Trade were often ineffectual due to a desire to keep on good terms with other European powers. The actions of the West Africa Squadron were "strictly Governed" by the treaties, and officers could be punished for overstepping their authority.
Commodore Sir George Ralph Collier, with the 36-gun HMS Creole as his flagship, was the first Commodore of the West Africa Squadron. On 19 September 1818, the navy sent him to the Gulf of Guinea with the orders, "You are to use every means in your power to prevent a continuance of the traffic in slaves." However, he had only six ships with which to patrol over 5,000 kilometres (3,000 mi) of coast. He served from 1818 to 1821.
In 1819 the Royal Navy created a naval station in West Africa at Freetown. This was the capital of the first British colony in West Africa, Sierra Leone. Most of the enslaved Africans freed by the squadron chose to settle in Sierra Leone as for fear of otherwise being re-enslaved. From 1821, the squadron also used Ascension Island as a supply depot, before this moved to Cape Town in 1832.
As the Royal Navy began interdicting slave ships, the slavers responded by abandoning their merchant ships in favour of faster ships, particularly Baltimore clippers. At first, the Royal Navy was often unable to catch these ships, however with the capture of slaver clippers and new faster ships from Britain the Royal Navy regained the upper hand. One of the most successful ships of the West Africa Squadron was one such captured ship, renamed HMS Black Joke. She successfully caught 11 slavers in one year.
Until 1835 the Royal Navy was only allowed to take foreign slavers that actually had slaves aboard. This meant the squadron could not interfere with vessels clearly equipped for the trade but without a cargo. It also gave slavers being pursued an incentive to throw their slaves overboard before capture to avoid the seizure of the vessel.
By the 1840s the West Africa Squadron had begun receiving paddle steamers, such as HMS Hydra, which proved superior in many ways to the sailing ships they replaced. The steamers were independent of the wind and their shallow draughts meant they could patrol the shallow shores and rivers. In the middle of the 19th century, there were around 25 vessels and 2,000 personnel with a further 1,000 local sailors involved in the effort.
The Royal Navy considered the West Africa Station one of the worst postings due to the high levels of tropical disease. This did however provide Royal Navy surgeons with the experience they would use to effectively fight such diseases, but at a huge cost in lives.
Britain pressed other nations into treaties to give the Royal Navy the right to search their ships for slaves. As the 19th century wore on, the Royal Navy also began interdicting slave trading in North Africa, the Middle East, and the Indian Ocean.
The United States Navy assisted the West Africa Squadron, starting in 1820 with HMS Cyane, which the US had captured from the Royal Navy in 1815. Initially the US contribution consisted of a few ships, but eventually the Webster-Ashburton Treaty of 1842 formalised the US contribution into the Africa Squadron.
In 1870, the Cape of Good Hope Station absorbed the West Africa Squadron.