Firstly, here are some facts, along with their sources, to avoid any doubt or scepticism about my motives. I am taking an arbitrary period of time, 1600-1900.
12.24 million Africans were forcibly embarked on transatlantic slave ships between 1601 and 1866. Source: SlaveVoyages.
Responsible transporting powers: Portugal/Brazil (46.5%), Great Britain (26.6%), France (11.3%), Spain/Uruguay (7.7%), Netherlands (4.5%), United States (2.5%) and Denmark/Baltic (0.9%). These figures identify the shipping powers, not necessarily those who captured the people.
Approximately 2.59 million Africans were transported across the Sahara between 1600 and 1880, according to Ralph Austen’s historical reconstruction. Source: LSE: Historical trans-Saharan trade research. The principal receiving states and territories were:
Morocco: Successive Moroccan sultanates, merchants and slaveholding households.
Ottoman Tripolitania (modern Libya): Ottoman provincial authorities, local rulers and merchants, especially those operating through Tripoli and Fezzan.
Egypt: Ottoman and subsequently Egyptian rulers, military establishments, merchants and private slave owners.
Algeria and Tunisia: Ottoman-era regencies and later local and colonial-era commercial networks.
Saharan intermediaries: Tuareg, Tebu, Arab and Amazigh (Berber) caravan operators and traders.
African suppliers: Political authorities, raiders and merchants in the western and central Sudan, including Bornu, the Hausa states and, during the nineteenth century, the Sokoto Caliphate. There is no reliable breakdown assigning a particular number to Morocco, Libya, Egypt or any other individual state. Sources: Ralph Austen, Oxford Research Encyclopedia (2024); Austen, The Mediterranean Islamic Slave Trade out of Africa; Adu Boahen, Journal of African History.
Approximately 1.9 million Africans were transported through Indian Ocean and eastern maritime slave-trading networks between 1601 and 1900, under one historical reconstruction. Source: Oxford Handbook of Modern African History.
The principal participants included:
Sultanate of Oman and Zanzibar: Omani rulers, plantation owners and merchants, particularly in the nineteenth century. Zanzibar and Pemba became major destinations for enslaved Africans, especially for clove production.
Portuguese colonial interests in Mozambique: Merchants, colonial commercial networks and African intermediaries involved in trafficking from southeastern Africa.
French colonial interests in the Mascarenes: Plantation owners and merchants importing enslaved Africans into Mauritius and Réunion.
Swahili coastal merchants: Commercial networks linking Zanzibar and other East African ports to inland suppliers and overseas markets.
Arabian and Persian Gulf trading networks: Merchants and slave owners supplying markets across Arabia, the Gulf and surrounding territories.
African inland suppliers: Local rulers, military leaders, raiders and merchants associated with communities including the Yao and several central African trading networks.
Source: Stephen Rockel, The 19th Century Slave Trade in Eastern Africa, Oxford Research Encyclopedia (2025).
Millions of Africans were enslaved within Africa itself without crossing the Atlantic, Sahara or Indian Ocean. No dependable single total exists for 1600–1900. Source: Patrick Manning, African slavery and the world economy.
African kingdoms involved in capturing, enslaving or selling people included Dahomey, Oyo, Asante, Kongo and others. Omani, Ottoman, North African and Arabian trading networks participated in separate regional systems. Source: Metropolitan Museum of Art.
Principal responsible political authorities included:
Sokoto Caliphate (modern northern Nigeria, Niger and neighbouring territories): An estimated 1 million to 2.5 million enslaved people lived within the Caliphate around 1900. Its rulers and emirates acquired captives through warfare, raids and tribute, using enslaved labour on farms and in households.
Dahomey (modern Benin): Royal authorities and private merchants acquired captives through military raids, purchases and regional trading networks.
Oyo Empire (modern Nigeria and Benin): Its rulers and armies enslaved captives during territorial expansion, supplying both domestic and Atlantic markets.
Asante Empire (modern Ghana): Its rulers, military commanders and merchants participated in enslavement, domestic slaveholding and exports.
Lunda and Chokwe states (modern Angola, DR Congo and Zambia): Political leaders, raiders and traders supplied captives to regional and Atlantic networks.
Sources: Lovejoy and Hogendorn, Slow Death for Slavery; Metropolitan Museum of Art; Robin Law, Slave-Raiders and Middlemen, 1989.
Note: The Sokoto estimate of 1–2.5 million is an estimate of people held in slavery at approximately the date stated, whereas the Atlantic, Saharan and Indian Ocean figures estimate people transported over several centuries. They cannot be directly added together or treated as equivalent national totals. Historical responsibility cannot be assigned solely to modern national boundaries. The traders operating through Tripoli were not all agents of a modern Libyan state, the Sultanate of Oman was not identical to modern Oman, and the African kingdoms did not correspond neatly to today’s countries. However, the named states, political authorities and trading networks provide a documented basis for identifying who participated in the enslavement, sale, transportation and exploitation of Africans between 1600 and 1900.
1803: Denmark’s abolition of its transatlantic slave trade took effect, following its 1792 decision. Source: SlaveVoyages.
1807: Britain abolished its participation in the slave trade. Source: UK Parliament.
1808: Britain began sustained naval operations against transatlantic slave traders through the West Africa Squadron. Source: Royal Navy.
1833–1838: Britain abolished slavery in most of its colonies, with emancipation beginning in 1834 and apprenticeship ending in 1838. Source: UK Parliament.
During its nineteenth-century suppression campaign, the Royal Navy captured more than 1,600 slave-trading vessels. Source: Royal Navy.
Britain’s naval suppression operations liberated approximately 150,000 enslaved Africans. Source: Royal Navy.
Approximately 17,000 British sailors died during the suppression campaign, predominantly from disease, according to a published Royal Navy historical estimate. The number is uncertain. Source: Royal Navy.
By 1850, approximately 25 vessels and 2,000 personnel were serving in Britain’s West Africa Squadron. Source: Royal Navy.
France deployed 77 anti-slavery cruisers between 1817 and 1831 in Atlantic suppression operations. Source: Oxford Research Encyclopedia.
The United States established an Africa Squadron in 1843, initially deploying four vessels. One historical account records 36 slave ships captured between 1844 and 1861. Source: US Naval History and Heritage Command.
1818: Britain and the Netherlands concluded a treaty providing mutual rights to intercept suspected slave traders and establish mixed courts. Source: British and Foreign State Papers.
1842: Portugal entered a major treaty with Britain providing for the suppression of slave trading. Source: UK Parliament historical records.
£29,752,271: British expenditure on suppressing the slave trade between 1808 and 1847, as estimated in Parliament in 1848. Source: Hansard, 24 March 1848
£153,434: Additional expenditure on bounties and related administration, bringing the parliamentary estimate to £29,905,705. Source: Hansard, 1848.
Approximately £4bn–£5bn: Illustrative modern purchasing-power equivalent of that £29.9 million, using nineteenth-century price levels. The original expenditure occurred over forty years, so no single-year inflation adjustment is exact. Source: Bank of England inflation calculator.
£706,454: Cost of Britain’s anti-slave-trade naval squadron in 1845. Source: Hansard, 1848.
£1m–£1.2m annually: Contemporary estimate of total suppression expenditure during the mid-1840s, including naval operations and supporting establishments. Roughly £150m–£200m annually in modern purchasing power. Source: Hansard, 1848
£20 million: Compensation paid to slave owners under Britain’s 1833 emancipation settlement. This represented approximately 40% of annual government expenditure at the time. It was not compensation paid to enslaved people. Source: UCL — Legacies of British Slave-Ownership.
£49,905,705: Combined suppression expenditure and slave-owner compensation cited in the 1848 parliamentary debate. Source: Hansard, 1848.
£32,481,325: Additional consumer costs attributed to higher sugar, molasses and rum prices during 1835–1846 by Henry Baillie MP. This figure was a disputed contemporary calculation. Source: Hansard, 1848.
£82,387,030: Total expenditure and additional consumer costs claimed by Baillie in 1848. This figure incorporates the disputed consumer-cost estimate and should not be described as audited government spending. Source: Hansard, 1848.
Approximately 1.8% of British national income annually, 1808–1867: An academic estimate by Chaim Kaufmann and Robert Pape of the wider economic cost of Britain’s abolitionist and slave-trade suppression policies. This includes economic consequences beyond direct government expenditure. Source: Kaufmann and Pape, International Organization (1999).
Approximately £55 billion annually: The economic equivalent of 1.8% of a modern UK economy of approximately £3 trillion. This is a GDP-share comparison, not an inflation-adjusted Treasury expenditure figure.
Approximately £3.3 trillion: The hypothetical cumulative modern economic equivalent of sixty years at £55 billion annually. This figure does not represent historical cash expenditure.
Given those facts, we can all agree that the historical data from almost three centuries ago is appalling in terms of human suffering. We can also agree that Great Britain made significant efforts to end slavery over 200 years ago, at a considerable national cost in terms of commitment, lives and national budgetary impact.
UK laws, Acts of Parliament and international treaties governed much of what happened at that time. Even the £20m compensation paid to slave owners under Britain’s 1833 emancipation settlement, a sum which represented some 40% of the annual government expenditure, was a legal requirement, however offensive it might appear now.
It was the law, and it is the law to which we must now turn.
The case for reparations is primarily a legal one. It cannot be a moral one, because were it so, the reparations made after the last two World Wars would simply be so insufficient on moral grounds that we would almost certainly find ourselves back at war again.
We have to use the law as it exists, and on that basis, it is a fundamental principle that a state is legally responsible for breaching international laws only if those laws were binding when the acts occurred. The principle of nullum crimen sine lege means, broadly, that conduct can only be deemed a criminal offence retrospectively if it was criminal under the law at the time.
Article 13 of the United Nations International Law Commission’s Articles on State Responsibility (2001) establishes this principle. The modern classification of slavery as a crime against humanity does not automatically create retrospective financial liability for conduct occurring between 1600 and 1900.
Furthermore, criminal responsibility is normally considered personal. In other words, you need a defendant who is accused as being responsible. We agree (although it might seem counterintuitive over seven or eight generations) that crimes against humanity have no limitation period, but this absence of limitation does not imply collective criminal guilt among subsequent generations or automatically create civil liability against a modern state.
I would also argue that a successful reparations claim must consist of five main parts: the establishment of an applicable legal obligation; the proof of its breach; an entitled claimant; a provable connection between the breach and the claimed loss; and a court with the mutually approved power to sit in judgement and, in the case of all parties concerned, a recognition in international law to abide fully by the court’s decision. Anything else would surely simply be considered geopolitical posturing.
Even if those five key elements for a legal case were in place, how on earth would responsibility be divided between the British state, individual traders and plantation owners of various nationalities, financiers, other European governments and the African tribes and states that captured and sold people?
The time scales involved make investigating individual actions and respective involvements, which varied over time, almost impossible. Then we have to ask whether the calculations more clearly distinguish between Britain’s period as a slave-trading power and its subsequent role in forcibly suppressing the trade. The historical record contains evidence of both, and any full assessment should set out how each is treated, even if no financial offset is ultimately allowed. Thirdly, how much of today’s economic inequality can be attributed specifically to historical enslavement rather than the many subsequent influences on national development?
There are credible and entirely justifiable arguments that slavery had lasting effects, but establishing the precise monetary share attributable to it is exceptionally difficult. Financial calculations based upon centuries of hypothetical lost earnings and compound interest are also not necessarily a verifiable set of calculations. The sums might add up, but the assumptions on which they are based may be faulty and need checking in order to reach some mutual agreement on their accuracy. In short, Britain’s subsequent abolition of slavery and costly international suppression campaign do not erase earlier wrongdoing, but neither do several miles of spreadsheets and a demand for legal action establish a present financial debt.
I would also add that I am not entirely convinced that the Reparations movement is being terribly consistent. If the underlying principle is that modern states should accept responsibility for the historical enslavement of Africans, then surely the activities of Middle Eastern, North African and African tribes, countries and nations raise questions about how consistently that principle is being applied. Currently, the central claims are only being directed at the UK and Europe (but not, so far as I understand it, Brazil) and are therefore geographically and historically specific. An equivalent claim involving the trans-Saharan or Indian Ocean trade would require identifying different victim populations, responsible authorities and present-day claimants. In brief, there is no comparable programme of financial claims against the Middle Eastern and North African states associated with those other slave-trading systems.
So there is no individual to be tried, and thus it cannot be a criminal case unless international law is changed and an entire state is tried as an individual. It cannot begin to be a civil legal case until a court is established where all agree that it has the authority to hear a case which is at least 300 years old. More importantly, unless all the other modern states associated with the trade were standing in court beside Great Britain for the financial allocation of historical responsibilities to be ascribed, it would appear to be a case being made against the one country that literally went into battle to end it.
I hesitate to suggest it, but inventing a nonexistent jurisdiction improves neither history nor morality.