The United Kingdom's fight against the slave trade in the Indian Ocean, particularly in Zanzibar, is seen through the prism of geopolitical relations and the British crown's colonial ambitions.

* Lire en français. The English translation is provided by the editorial staff, who are solely responsible for any inaccuracies.

At a time when debates on humanitarian intervention have resurfaced in the wake of current conflicts, it is worth looking at the history of this concept and its place in international law. Far from being born out of the Second World War or even the Cold War, the idea of intervening in a country's internal affairs in the name of human rights actually originated with the British fight against the slave trade and slavery in the 19th century.

This book, the result of a thesis by Raphaël Cheriau, an associate member of the Richard Roland Mousnier Centre and the Centre for War Studies in Dublin, seeks to historicise the notion of humanitarian intervention. Drawing in particular on British and French diplomatic archives, it offers a re-reading of the fight against the slave trade in the Zanzibar archipelago, goes back to the sources of international law and its contradictions, and then discusses the idea that this repression, carried out by the Royal Navy, may in fact have had colonialist aims.

A strategic territory

Raphaël Cheriau's investigation takes place in Zanzibar. This archipelago in the heart of the Indian Ocean was a strategic location for the players involved. At the beginning of the period, this territory was part of the Omani colonial empire, which stretched between Kenya and Tanzania, and of which the Sultan made his capital. The archipelago was thus linked to its immediate environment by political, economic, religious and cultural ties, and was one of the keys to the Omani "thalassocracy" in the Indian Ocean.

But Zanzibar was also on the route to India, and therefore an essential crossing point for the British, who were seeking to control the Persian Gulf passages. The area was also strategic for the French, who were already extending their colonial empire to Djibouti, Mayotte and Réunion. Combined with some of the world's largest production of ivory, gum and cloves, it's easy to see why these small islands in the Indian Ocean were so coveted. It is "the place where the economies of East Africa, the Indian Ocean and the world met".

Because of its strategic position and resources, Zanzibar was also a place of transit for many slaves: many people were transferred there to supply the continent, but also the other islands in the Indian Ocean. In fact, around 1840, Zanzibar became the largest slave market in East Africa and it is estimated that between 15,000 and 25,000 men, women and children passed through there in the 1860s, rising to nearly 770,000 throughout the century. The image often used is that of these dhows, trading ships containing a variety of cargoes and sometimes a few slaves, "one of the many colonial icons that embodied the fascinating complexity of the Middle East in Europe".

A complex British ambition

It is in this particular territory that Raphaël Cheriau situates his study and shows how the British, through the Royal Navy, sought to prohibit the movement of slaves at the same time as they were establishing a lasting presence in the region: "this archipelago in the Indian Ocean was one of the places in the world where the abolitionist movement and colonial expansion collided in a most surprising and singular way", writes the author.

The British fight against the slave trade, which had been going on for several decades in the Atlantic, soon reached its limits in the Indian Ocean. Raphaël Cheriau shows that the resources available to the Royal Navy fell far short of what was needed. There were not enough men or ships to cope with the 600 or so dhows carrying the slaves, and the officers had no command of the local languages and codes. Eyewitness accounts show that the British were unable to act effectively.

They also point to a discrepancy between the strength of the abolitionist discourse and the intense publicity given in Europe to the operations carried out, on the one hand, and the reality on the ground, on the other: "the failure of the Royal Navy was not so much the result of a lack of appropriate material resources as the fruit of an inability on the part of the British to interpret and understand the reality they faced in the Indian Ocean, as well as the inextricable complexity of the rules imposed on them by respect for international law".

In Great Britain, however, the abolitionist aims of the state were an integral part of the Victorian era, and the author recalls the "importance of abolitionism in the construction of the British identity and its national and international policy". As a result, public opinion was regularly mobilised in the fight against the slave trade: each capture was publicised in the press, then by associations and politicians, and historiographically taken up as a "key aspect of the British historical novel".

In fact, with the help of well-documented statistical data, the author shows that catches were rare and ultimately involved few rescued slaves: "this false view of the nature of the slave trade influenced not only European public opinion but also some of the historians who subsequently took an interest in these issues". The cover of the book illustrates the famous shot of the H.M.S. Daphne leaving the coast of East Africa in November 1868, with freed slaves on board. This image, which was widely circulated afterwards, has remained a symbol of Britain's humanitarian action.

What's more, the scope of the liberations needs to be qualified: many of the freed slaves went on to become "indentured servants", a status that was hardly more enviable and amounted to forced labour: "almost all of those who were thus 'freed' experienced new forms of servitude".

From abolitionism to colonialism

Taking these difficulties as a starting point, Raphaël Cheriau describes the various phases of the British presence in Zanzibar, which became increasingly strong.

In 1869, Great Britain took the first step towards interference in Zanzibar by setting up a Vice-Admiralty Court, responsible for combating the slave trade locally. Little by little, "the diplomatic mission was transformed into a demonstration of colonial power, breaking with the rules of international law and its initial humanitarian spirit". In practice, the Sultan lost part of his sovereignty, which was now entrusted to the British consul. Here, "the British Empire had moved from informal economic and political domination to a direct takeover of territory of strategic, community or humanitarian interest".

The following decade saw the establishment of the Bartle Frere mission, named after a humanitarian who travelled in the region and then led an active public campaign in Great Britain to combat the trade more effectively. These high-profile actions enabled anti-trafficking campaigners to relaunch missions such as the HMS London, which was active between 1874 and 1883 and consisted of a gunboat and small boats. This project was driven in particular by the discourses of explorers such as David Livingstone, whose descriptions of slavery in East Africa were reproduced in Great Britain and fuelled discourses that combined abolitionism and colonial necessity. They were disseminated in particular by the very active BFASS (British and Foreign Anti-Slavery Society, founded in 1838), and behind it by public opinion and some members of parliament. But these missions were also disappointing, leading to a "public confession of impotence on the part of the largest navy in the world, even on an island as small as Zanzibar".

A further step was taken in the 1880s, when British pressure intensified. Following a local revolt against German agents, Great Britain and Germany agreed to set up a blockade on Zanzibar, which lasted from December 1888 to October 1889. The Royal Navy, the "policeman of the seas", justified this decision on humanitarian grounds, as a further step towards control of this part of the world.

The author shows how British leaders used the argument of the fight against the slave trade in the last decades of the 19th century to justify imperialist policies: "intervention needed a humanitarian cause to overcome divergent political interests and win unanimous support in the political arena and in public opinion". This is what the author calls "humanitarian imperialism".

One of the interests of the book is the questioning of the initial British colonisation plan. According to the author, the sources show that there was no plan for colonisation at the very beginning, but that it was built up over time, as a result of the "complex, changing, paradoxical and often unpredictable" interactions between abolitionist policies and their failures, as well as the more general context of African colonisation. The fact remains that the British presence intensified: in 1890, Zanzibar became a de facto British protectorate.

A history of international law and Franco-British tensions in the Indian Ocean

However, one obstacle stood in the way of the whole process: France. Seen from the outset as a thorn in the side of these "humanitarian missions", France was regularly blamed for the Royal Navy's disappointing results. At issue was the legal question of the right to visit and board ships likely to be carrying slaves.

The question of the nationality of ships was thus at the heart of the issues, and the author recalls that, although flags were linked to an owning nation, "dhows [...] were not linked to any nation, at least not in the sense that Europeans gave to the word at the time. They belonged to the Indian Ocean, its many shores and its many communities. It was not a nation but the ocean, navigation and Islam [...] that united them". It is easy to see how difficult it is to establish an international legal framework.

In these debates, there was a divergence in the conception of the law, particularly between France and Great Britain. In the name of its sovereignty, France refused to allow the British navy to intervene on its dhows; the British, on the other hand, theorised that in the fight against the slave trade and flags of convenience, the right to interfere was superior, in the name of civilisation. Great Britain, "the most civilised of all nations", developed the notion of "humanitarian intervention", which it sought to have recognised in international law. France became "the defender of national sovereignty against the British desire to establish an international system of justice and policing of the seas in the name of repression of the slave trade and the defence of humanity".

Various meetings took place between 1860 and 1905 to try and establish the framework for these interventions: "in the eyes of the British, the fight against the slave trade, as a humanitarian reason, fully justified challenging the sovereignty of States and the principle of freedom of navigation on the high seas". But France, for whom "the question of sovereignty took precedence over that of humanitarianism", refused to give in on the question of visiting rights, i.e. the right of the British navy to inspect and seize foreign ships. This measure existed at the time to counter piracy, but the Royal Navy sought to extend it to counter the slave trade, which constituted a "revolution in international law both in theory and in practice". Throughout the period, France, a direct colonial rival, did not give in: many dhows flew the French flag and, while it is true that some slave traders had French papers, the author puts their importance into perspective: "tricoloured dhows were not the main players in this trade, even though they undoubtedly made a significant contribution to it".

As early as 1841, a diplomatic crisis broke out between the two nations, with France refusing to ratify the treaty on visiting rights, while legislation on flags was being perfected. There were around sixty contentious cases between France and Great Britain between 1858 and 1914. In 1862, the two countries signed a treaty recognising the independence and sovereignty of Zanzibar, but this was quickly undermined by colonial ambitions and finally rendered null and void by the partition of Berlin in 1885.

A cross-reading of the French and British archives reveals the complexity of diplomatic relations between the two countries and the genesis of an attempt at international law on these issues. On several occasions, France seemed open to extending visiting rights, but always ended up qualifying or backing down: the British were regularly contradicted or even humiliated.

The Brussels Conference opened in 1890, a few months after the end of the blockade, and 17 nations were represented. This diplomatic meeting was a key moment in the abolitionist struggle, but also, as the author shows, in the manipulation of this issue for colonial ends. Here again, two visions clashed: France reiterated the primacy of national sovereignty in the control and regulation of its ships, while Great Britain countered with the superior right to repress the slave trade, and laid the foundations for colonial control: "in Brussels, humanitarianism and imperialism went hand in hand without any ambiguity". The first act of the Conference asserted that only colonisation could put a definitive end to the slave trade, cynically overlooking the violence during the blockade and the massacres in the Belgian Congo. As the first step towards internationalising the struggle, the Brussels Conference sought to extend the prerogatives of the Royal Navy in the Indian Ocean. France countered by agreeing to more restrictive legislation on blockades, but finally refused to ratify the Brussels Act in June 1891, which did not stop British missions: military and diplomatic operations of a humanitarian nature, referred to in the sources as "interventions of humanity", multiplied.

Some fifteen years later, in 1905, the debate moved to the International Court of Justice in The Hague, following the Muscat dhow affair, in which France and Great Britain were once again pitted against each other. In Muscat, the capital of Oman, in an area of the Indian Ocean that had become an informal British pre-square and then a protectorate in 1890, France wanted to establish a coal depot and reopen a consulate. Faced with British pressure, the Sultan of Oman refused. Furthermore, in 1903, five sailors, including three French "protégés", were arrested by the Royal Navy and convicted by the Sultan of Oman: the issue of flags of convenience resurfaced. Muscat became a point of tension between the two powers. In response, France threatened military intervention and sent its gunboat. This casus belli was finally settled diplomatically in The Hague, resulting in a "subtle legal, political and colonial compromise", giving nations back control of their flags. Finally, after half a century of tensions, "the Hague arbitration put an end to the Franco-British colonial rivalry that had crystallised throughout the second half of the nineteenth century around the dhows flying the French flag in Zanzibar and Oman".

Abolition of slavery in Zanzibar and the persistence of the colonial question

Finally, up until 1914, while colonial domination was being established on the African continent, the colonial powers, led by France and Great Britain, were also seeking to dominate the seas. On the eve of the First World War, Zanzibar, which had officially abolished slavery in 1909, was no longer a key player in the fight against the slave trade, which had moved within a continent that was still in European hands. This has given rise to the myth that colonisation put an end to slavery in Africa: "the European powers played down the existence of the slave trade and slavery once they had established their domination", says the author.

This book, the result of a thesis that was brilliantly made accessible to a wide readership, plunges us into a world that is relatively unfamiliar to Westerners: the fight against the slave trade in the Indian Ocean and the sometimes intense Franco-British rivalries that took place there. While the author puts the idea of an initial colonisation plan into perspective, pointing out that "abolitionism is not imperialistic by nature, but rather opportunistic", he shows the extent to which the Europeans used and abused these interventions of humanity to justify their ever-stronger control of the African coasts and seas.