|Slavery in the United States||American West||Civil Rights Movement|
William Wilberforce, only son of Robert Wilberforce (1728–1768) and Elizabeth Bird (1730–1798), was born in Kingston upon Hull on 24th August 1759. William's father, who was a wealthy merchant, died when he was seven years old and for a time was brought up by an uncle and aunt.
William came under the influence of his aunt, who was a strong supporter of John Wesley and the Methodist movement. According to his biographer, John Wolffe: "Meanwhile his aunt Hannah, an admirer of George Whitefield and friendly with the Methodists, influenced him towards evangelicalism. His grandfather and mother, however, took fright, and brought him back to live in Hull, where every effort was made to distract him from such enthusiastic religion."
At seventeen Wilberforce was sent to St. John's College. Following the deaths of his grandfather in 1776 and his childless uncle William in 1777, Wilberforce was an extremely wealthy man. Wilberforce was shocked by the behaviour of his fellow students at the University of Cambridge and later wrote: "I was introduced on the very first night of my arrival to as licentious a set of men as can well be conceived. They drank hard, and their conversation was even worse than their lives." One of Wilberforce's friends at university was William Pitt, who was later to become Britain's youngest ever Prime Minister.
Following the deaths of his grandfather in 1776 and his childless uncle William in 1777, Wilberforce was an extremely wealthy man. After leaving university he showed no interest in the family business, and while still at Cambridge he decided to pursue a political career and at the age of twenty, he decided to become a candidate in the forthcoming parliamentary election in Kingston upon Hill in September 1780. His opponent was Charles Watson-Wentworth, a rich and powerful member of the nobility, and Wilberforce had to spend nearly £9,000 to become elected. In the House of Commons Wilberforce supported the the Tory government led by William Pitt.
The historian, Ellen Gibson Wilson, has pointed out: "Wilberforce was little over five feet tall, a frail and elfin figure who in his later years weighed well under 100 pounds. His charm was legendary, his conversation delightful, his oratory impressive. He dressed in the colourful finery of the day and adorned any salon with his amiable manner. Yet his object in life - no less than the transformation of a corrupt society through serious religion - was solemn... Wilberforce, although he rejected a party label, was deeply conservative and a loyal supporter of the government led by his friend William Pitt."
In 1784 Wilberforce became converted to Evangelical Christianity. He joined the Clapham Set, a group of evangelical members of the Anglican Church, centered around Henry Venn, rector of Clapham Church in London. As a result of this conversion, Wilberforce became interested in the subject of social reform. Other members included Hannah More, Granville Sharp, Henry Thornton, Zachary Macaulay, James Stephen, Edward James Eliot, Thomas Gisbourne, John Shore and Charles Grant.
In June 1786 Thomas Clarkson published Essay on the Slavery and Commerce of the Human Species, Particularly the African. As Ellen Gibson Wilson has pointed out: "A substantial book (256 pages), it traced the history of slavery to its decline in Europe and arrival in Africa, made a powerful indictment of the slave system as it operated in the West Indian colonies and attacked the slave trade supporting it. In reading it, one is struck by its raw emotion as much as by its strong reasoning." William Smith argued that the book was a turning-point for the slave trade abolition movement and made the case "unanswerably, and I should have thought, irresistibly".
In 1787 Thomas Clarkson, William Dillwyn and Granville Sharp formed the Society for the Abolition of the Slave Trade. Although Sharp and Clarkson were both Anglicans, nine out of the twelve members on the committee, were Quakers. This included John Barton (1755-1789); George Harrison (1747-1827); Samuel Hoare Jr. (1751-1825); Joseph Hooper (1732-1789); John Lloyd (1750-1811); Joseph Woods (1738-1812); James Phillips (1745-1799) and Richard Phillips (1756-1836). Influential figures such as Charles Fox, John Wesley, Josiah Wedgwood, James Ramsay, and William Smith gave their support to the campaign. Clarkson was appointed secretary, Sharp as chairman and Hoare as treasurer.
Clarkson approached another sympathiser, Charles Middleton, the MP for Rochester, to represent the group in the House of Commons. He rejected the idea and instead suggested the name of William Wilberforce, who "not only displayed very superior talents of great eloquence, but was a decided and powerful advocate of the cause of truth and virtue." Lady Middleton wrote to Wilberforce who replied: "I feel the great importance of the subject and I think myself unequal to the task allotted to me, but yet I will not positively decline it." Wilberforce's nephew, George Stephen, was surprised by this choice as he considered him a lazy man: "He worked out nothing for himself; he was destitute of system, and desultory in his habits; he depended on others for information, and he required an intellectual walking stick."
Charles Fox was unsure of Wilberforce's commitment to the anti-slavery campaign. He wrote to Thomas Walker: "There are many reasons why I am glad (Wilberforce) has undertaken it rather than I, and I think as you do, that I can be very useful in preventing him from betraying the cause, if he should be so inclined, which I own I suspect. Nothing, I think but such a disposition, or a want of judgment scarcely credible, could induce him to throw cold water upon petitions. It is from them and other demonstrations of the opinion without doors that I look for success."
In May 1788, Charles Fox precipitated the first parliamentary debate on the issue. He denounced the "disgraceful traffic" which ought not to be regulated but destroyed. He was supported by Edmund Burke who warned MPs not to let committees of the privy council do their work for them. William Dolben described shipboard horrors of slaves chained hand and foot, stowed like "herrings in a barrel" and stricken with "putrid and fatal disorders" which infected crews as well. With the support of Wilberforce Samuel Whitbread, Charles Middleton and William Smith, Dolben put forward a bill to regulate conditions on board slave ships. The legislation was initially rejected by the House of Lords but after William Pitt threatened to resign as prime minister, the bill passed 56 to 5 and received royal assent on 11th July.
Wilberforce also became involved in other areas of social reform. In August 1789 Wilberforce stayed with Hannah More at her cottage in Blagdon, and on visiting the nearby village of Cheddar and according to William Roberts, the author of Memoirs of the Life and Correspondence of Mrs. Hannah More (1834): they were appalled to find "incredible multitudes of poor, plunged in an excess of vice, poverty, and ignorance beyond what one would suppose possible in a civilized and Christian country". As a result of this experience, More rented a house at Cheddar and engaged teachers to instruct the children in reading the Bible and the catechism. The school soon had 300 pupils and over the next ten years the More sisters opened another twelve schools in the area where the main objective was "to train up the lower classes to habits of industry and virtue".
Michael Jordan, the author of The Great Abolition Sham (2005) has pointed out that More shared Wilberforce's reactionary political views: "More set up local schools in order to equip impoverished pupils with an elementary grasp of reading. This, however, was where her concern for their education effectively ended, because she did not offer her charges the additional skill of writing. To be able to read was to open a door to good ideas and sound morality (most of which was provided by Hannah More through a series of religious pamphlets); writing, on the other hand, was to be discouraged, since it would open the way to rising above one's natural station."
Wilberforce's biographer, John Wolffe, has argued: "Following the publication of the privy council report on 25 April 1789, Wilberforce marked his own delayed formal entry into the parliamentary campaign on 12 May with a closely reasoned speech of three and a half hours, using its evidence to describe the effects of the trade on Africa and the appalling conditions of the middle passage. He argued that abolition would lead to an improvement in the conditions of slaves already in the West Indies, and sought to answer the economic arguments of his opponents. For him, however, the fundamental issue was one of morality and justice. The Society for the Abolition of the Slave Trade was very pleased with the speech and sent its thanks for his "unparalleled assiduity and perseverance".
The House of Commons agreed to establish a committee to look into the slave trade. Wilberforce said he did not intend to introduce new testimony as the case against the trade was already in the public record. Ellen Gibson Wilson, a leading historian on the slave trade has argued: "Everyone thought the hearing would be brief, perhaps one sitting. Instead, the slaving interests prolonged it so skilfully that when the House adjourned on 23 June, their witnesses were still testifying."
James Ramsay, the veteran campaigner against the slave trade, was now extremely ill. He wrote to Thomas Clarkson on 10th July 1789: "Whether the bill goes through the House or not, the discussion attending it will have a most beneficial effect. The whole of this business I think now to be in such a train as to enable me to bid farewell to the present scene with the satisfaction of not having lived in vain." Ten days later Ramsay died from a gastric haemorrhage. The vote on the slave trade was postponed to 1790.
Wilberforce initially welcomed the French Revolution as he believed that the new government would abolish the country's slave trade. He wrote to Abbé de la Jeard on 17th July 1789 commenting that "I sympathize warmly in what is going forward in your country." Wilberforce intended to visit France but he was persuaded by friends that it would be dangerous for an English politician to be in the country during a revolution. Wilberforce therefore asked Clarkson to visit Paris on behalf of himself and the Society for the Abolition of the Slave Trade.
Clarkson was welcomed by the French abolitionists and later that month the government published A Declaration of the Rights of Man asserting that all men were born and remained free and equal. However, the visit was a failure as Clarkson could not persuade the French National Assembly to discuss the abolition of the slave trade. Marquis de Lafayette said "he hoped the day was near at hand, when two great nations, which had been hitherto distinguished only for their hostility would unite in so sublime a measure (abolition) and that they would follow up their union by another, still more lovely, for the preservation of eternal and universal peace."
On his return to England Thomas Clarkson continued to gather information for the campaign against the slave-trade. Over the next four months he covered over 7,000 miles. During this period he could only find twenty men willing to testify before the House of Commons. He later recalled: "I was disgusted... to find how little men were disposed to make sacrifices for so great a cause." There were some seamen who were willing to make the trip to London. One captain told Clarkson: "I had rather live on bread and water, and tell what I know of the slave trade, than live in the greatest affluence and withhold it."
Wilberforce believed that the support for the French Revolution by the leading members of the Society for the Abolition of Slave Trade was creating difficulties for his attempts to bring an end to the slave trade in the House of Commons. He told Thomas Clarkson: "I wanted much to see you to tell you to keep clear from the subject of the French Revolution and I hope you will." Isaac Milner, after a long talk with Clarkson, commented to Wilberforce: "I wish him better health, and better notions in politics; no government can stand on such principles as he maintains. I am very sorry for it, because I see plainly advantage is taken of such cases as his, in order to represent the friends of Abolition as levellers."
On 18th April 1791 Wilberforce introduced a bill to abolish the slave trade. Wilberforce was supported by William Pitt, William Smith, Charles Fox, Richard Brinsley Sheridan, William Grenville and Henry Brougham. The opposition was led by Lord John Russell and Colonel Banastre Tarleton, the MP for Liverpool. One observer commented that it was "a war of the pigmies against the giants of the House". However, on 19th April, the motion was defeated by 163 to 88.
In March 1796, Wilberforce's proposal to abolish the slave trade was defeated in the House of Commons by only four votes. At least a dozen abolitionist MPs were out of town or at the new comic opera in London. Wilberforce wrote in his diary: "Enough at the Opera to have carried it. I am permanently hurt about the Slave Trade." Thomas Clarkson commented: "To have all our endeavours blasted by the vote of a single night is both vexatious and discouraging." It was a terrible blow to Clarkson and he decided to take a rest from campaigning.
In 1804, Clarkson returned to his campaign against the slave trade and toured the country on horseback obtaining new evidence and maintaining support for the campaigners in Parliament. A new generation of activists such as Henry Brougham, Zachary Macaulay and James Stephen, helped to galvanize older members of the Society for the Abolition of the Slave Trade.
William Wilberforce introduced an abolition bill on 30th May 1804. It passed all stages in the House of Commons and on 28th June it moved to the House of Lords. The Whig leader in the Lords, Lord Grenville, said as so many "friends of abolition had already gone home" the bill would be defeated and advised Wilberforce to leave the vote to the following year. Wilberforce agreed and later commented "that in the House of Lords a bill from the House of Commons is in a destitute and orphan state, unless it has some peer to adopt and take the conduct of it".
In 1805 the bill was once again presented to the House of Commons. This time the pro-slave trade MPs were better organised and it was defeated by seven votes. Wilberforce blamed "Great canvassing of our enemies and several of our friends absent through forgetfulness, or accident, or engagements preferred from lukewarmness." Clarkson now toured the country reactivating local committees against the slave trade in an attempt to drum up the support needed to get the legislation through parliament.
In February, 1806 Lord Grenville was invited by the king to form a new Whig administration. Grenville, was a strong opponent of the slave trade. Grenville was determined to bring an end to British involvement in the trade. Thomas Clarkson sent a circular to all supporters of the Society for the Abolition of the Slave Trade claiming that "we have rather more friends in the Cabinet than formerly" and suggested "spontaneous" lobbying of MPs.
Grenville's Foreign Secretary, Charles Fox, led the campaign in the House of Commons to ban the slave trade in captured colonies. Clarkson commented that Fox was "determined upon the abolition of it (the slave trade) as the highest glory of his administration, and as the greatest earthly blessing which it was the power of the Government to bestow." This time there was little opposition and it was passed by an overwhelming 114 to 15.
In the House of Lords Lord Greenville made a passionate speech where he argued that the trade was "contrary to the principles of justice, humanity and sound policy" and criticised fellow members for "not having abolished the trade long ago". When the vote was taken the bill was passed in the House of Lords by 41 votes to 20.
In January 1807 Lord Grenville introduced a bill that would stop the trade to British colonies on grounds of "justice, humanity and sound policy". Ellen Gibson Wilson has pointed out: "Lord Grenville masterminded the victory which had eluded the abolitionist for so long... He opposed a delaying inquiry but several last-ditch petitions came from West Indian, London and Liverpool shipping and planting spokesmen.... He was determined to succeed and his canvassing of support had been meticulous." Grenville addressed the Lords for three hours on 4th February and when the vote was taken it was passed by 100 to 34.
Wilberforce commented: "How popular Abolition is, just now! God can turn the hearts of men". During the debate in the House of Commons the solicitor-general, Samuel Romilly, paid a fulsome tribute to Wilberforce's unremitting advocacy in Parliament. The trade was abolished by a resounding 283 to 16. According to Clarkson, it was the largest majority recorded on any issue where the House divided. Romilly felt it to be "the most glorious event, and the happiest for mankind, that has ever taken place since human affairs have been recorded."
Under the terms of the Abolition of the Slave Trade Act (1807) British captains who were caught continuing the trade were fined £100 for every slave found on board. However, this law did not stop the British slave trade. If slave-ships were in danger of being captured by the British navy, captains often reduced the fines they had to pay by ordering the slaves to be thrown into the sea.
In 1807 Thomas Clarkson published his book History of the Abolition of the African Slave Trade. He dedicated it to the nine of the twelve members of Lord Grenville's Cabinet who supported the Abolition of the Slave Trade Act and to the memories of William Pitt and Charles Fox. Clarkson played a generous tribute to the work of Wilberforce: "For what, for example, could I myself have done if I had not derived so much assistance from the committee? What could Mr Wilberforce have done in parliament, if I... had not collected that great body of evidence, to which there was such a constant appeal? And what could the committee have done without the parliamentary aid of Mr Wilberforce?"
Some people involved in the anti-slave trade campaign such as Thomas Fowell Buxton, argued that the only way to end the suffering of the slaves was to make slavery illegal. Wilberforce disagreed, he believed that at this time slaves were not ready to be granted their freedom. He pointed out in a pamphlet that he wrote in 1807 that: "It would be wrong to emancipate (the slaves). To grant freedom to them immediately, would be to insure not only their masters' ruin, but their own. They must (first) be trained and educated for freedom."
In July, 1807, members of the Society for the Abolition of Slave Trade established the African Institution, an organization that was committed to watch over the execution of the law, seek a ban on the slave trade by foreign powers and to promote the "civilization and happiness" of Africa. The Duke of Gloucester became the first president and members of the committee included Wilberforce, Thomas Clarkson, Henry Brougham, James Stephen, Granville Sharp and Zachary Macaulay.
Wayne Ackerson, the author of The African Institution and the Antislavery Movement in Great Britain (2005) has argued: "The African Institution was a pivotal abolitionist and antislavery group in Britain during the early nineteenth century, and its members included royalty, prominent lawyers, Members of Parliament, and noted reformers such as William Wilberforce, Thomas Clarkson, and Zachary Macaulay. Focusing on the spread of Western civilization to Africa, the abolition of the foreign slave trade, and improving the lives of slaves in British colonies, the group's influence extended far into Britain's diplomatic relations in addition to the government's domestic affairs. The African Institution carried the torch for antislavery reform for twenty years and paved the way for later humanitarian efforts in Great Britain."
Wilberforce made it clear that he considered the African Institution should do what it could to convert Africans to Christianity. In 1811 he wrote: "In truth there is a peculiar call on our sensibility in the present instance, for in proportion as the lot of slaves is hard in the world, we ought to rejoice in every opportunity of bringing them under their present sufferings, and secure for them a rich compensation of reversionary happiness."
In 1808 the Clapham Set decided to transfer the Sierra Leone Company to the crown, the British government accepted Wilberforce's suggestion that Thomas Perronet Thompson would be a suitable governor. He introduced an extensive range of reforms and made serious allegations against the colony's former administrators. Stephen Tomkins, the author of William Wilberforce (2007) has argued: "He (Perronet Thompson) single-handedly abolished apprenticeship and freed the slaves. He filed scandalised reports to the colonial office. Wilberforce told him he was being rash and hasty, and he and his colleagues voted unanimously for his dismissal. Wilberforce advised him to go quietly for the sake of his career."
In the General Election following the passing of the Abolition of the Slave Trade Act Wilberforce was challenged by a political opponent. He won but the hard contest had left him "thin and old beyond his years". In 1811 he decided to give up the county seat for reasons of health. Lord Calthorpe offered him a pocket borough at Bramber and he was returned from there in 1812 without having to leave his holiday home.
Francis Burdett was a supporter of Wilberforce's campaign against the slave trade. In 1816 he attacked Wilberforce when he refused to complain about the suspension of Habeas Corpus, during the campaign for parliamentary reform. Burdett commented: "How happened it that the honourable and religious member was not shocked at Englishmen being taken up under this act and treated like African slaves?" Wilberforce replied that Burdett was opposing the government in a deliberate scheme to destroy the liberty and happiness of the people."
In 1823 Thomas Clarkson, Thomas Fowell Buxton, William Allen, James Cropper and Zachary Macaulay formed the Society for the Mitigation and Gradual Abolition of Slavery. Buxton eventually persuaded Wilberforce to join his campaign but as he had retired from the House of Commons in 1825, he did not play an important part in persuading Parliament to bring an end to slavery.
At the conference in May 1830, the Society for the Mitigation and Gradual Abolition of Slavery agreed to drop the words "gradual abolition" from its title. It also agreed to support the plan put forward by Sarah Wedgwood for a new campaign to bring about immediate abolition. Wilberforce, who had always been reluctant to campaign against slavery, agreed to promote the organisation. Thomas Clarkson praised Wilberforce for taking this brave move. He replied: "I cannot but look back to those happy days when we began our labours together; or rather when we worked together - for he began before me - and we made the first step towards that great object, the completion of which is the purpose of our assembling this day."
William Wilberforce died on 29th July, 1833. One month later, Parliament passed the Slavery Abolition Act that gave all slaves in the British Empire their freedom. When Thomas Clarkson heard the news he locked the door of his study and his wife heard him "in an agony of grief weeping and uttering loud lamentations."
In 1834 Robert Wilberforce and Samuel Wilberforce, began work on their father's biography. The book was published in 1838. As Ellen Gibson Wilson, the author of Thomas Clarkson (1989), pointed out: "The five volumes which the Wilberforces published in 1838 vindicated Clarkson's worst fears that he would be forced to reply. How far the memoir was Christian, I must leave to others to decide. That it was unfair to Clarkson is not disputed. Where possible, the authors ignored Clarkson; where they could not they disparaged him. In the whole rambling work, using the thousands of documents available to them, they found no space for anything illustrating the mutual affection and regard between the two great men, or between Wilberforce and Clarkson's brother."
Wilson goes on to argue that the book has completely distorted the history of the campaign against the slave-trade: "The Life has been treated as an authoritative source for 150 years of histories and biographies. It is readily available and cannot be ignored because of the wealth of original material it contains. It has not always been read with the caution it deserves. That its treatment of Clarkson, in particular, a deservedly towering figure in the abolition struggle, is invalidated by untruths, omissions and misrepresentations of his motives and his achievements is not understood by later generations, unfamiliar with the jealousy that motivated the holy authors. When all the contemporary shouting had died away, the Life survived to take from Clarkson both his fame and his good name. It left us with the simplistic myth of Wilberforce and his evangelical warriors in a holy crusade.
Eventually, Robert Wilberforce and Samuel Wilberforce apologized for what they had done to Clarkson: "As it is now several years since the conclusion of all differences between us, and we can take a more dispassionate view than formerly of the circumstances of the case, we think ourselves bound to acknowledge that we were in the wrong in the manner in which we treated you in the memoir of our father.... we are conscious that too jealous a regard for what we thought our father's fame, led us to entertain an ungrounded prejudice against you and this led us into a tone of writing which we now acknowledge was practically unjust."
(1) Charles Fox, letter to Thomas Walker (May 1788)
There are many reasons why I am glad (Wilberforce) has undertaken it rather than I, and I think as you do, that I can be very useful in preventing him from betraying the cause, if he should be so inclined, which I own I suspect. Nothing, I think but such a disposition, or a want of judgment scarcely credible, could induce him to throw cold water upon petitions. It is from them and other demonstrations of the opinion without doors that I look for success.
(2) William Wilberforce, letter to Thomas Clarkson (August 1793)
We have long acted together in the greatest cause which ever engaged the efforts of public men, and so I trust we shall continue to act with one heart and one hand, relieving our labours as hitherto with the comforts of social intercourse. And notwithstanding what you say of your irreconcilable hostility to the present administration, and of my bigoted attachment to them, I trust if our lives are spared, that after the favourite wish of our hearts has been gratified by the Abolition of the Slave Trade, there may still be many occasions on which we may co-operate for the glory of our Maker, and the improvement and happiness of our fellow-creatures.
For what, for example, could I myself have done if I had not derived so much assistance from the committee? What could Mr Wilberforce have done in parliament, if I... had not collected that great body of evidence, to which there was such a constant appeal? And what could the committee have done without the parliamentary aid of Mr Wilberforce?
(4) Stephen Tomkins, The Guardian(3rd August, 2010)
William Wilberforce, the most celebrated campaigner against the slave trade, was also implicated in slavery and the trade, according to a forthcoming book about him and the Clapham sect, written, it so happens, by me. Having given 20 years of his life to the struggle, after the Abolition Act was passed in 1807, he allowed the abolitionist colony of Sierra Leone, which the Clapham sect managed, to use slave labour and buy and sell slaves.
This is not a claim I make with the relish of trying to bring down an over-venerated icon a peg or two. I'm a critical fan of Wilberforce for his central role in the astounding achievement in abolition, which without his stamina would certainly have failed.
Neither is it a case of reading too much between the lines of meagre evidence. The facts are indisputably clear from colonial office manuscripts in the Public Record Office, whatever interpretation one might put on them. It's just a matter of information that biographers of Wilberforce have not picked up on – a point I make without any great arrogance, having been one of them myself.
The story starts 15 years before the abolition of the slave trade, when Wilberforce and the Clapham sect founded the colony of Sierra Leone as a new front in the abolition campaign – to resettle former slaves and establish legitimate commerce with Africa. They continued to effectively manage it when it became a crown colony on the abolition of the slave trade in 1807.
After abolition, the British navy patrolled the Atlantic seizing slave ships. The crew were arrested, but what to do with the African captives? With the knowledge and consent of Wilberforce and friends, they were taken to Sierra Leone and put to slave labour in Freetown.
They were called "apprentices", but they were slaves. The governor of Sierra Leone paid the navy a bounty per head, put some of the men to work for the government, and sold the rest to landowners. They did forced labour, under threat of punishment, without pay, and those who escaped to neighbouring African villages to work for wages were arrested and brought back. Women were "given away".
The one difference by which apprenticeship was distinguished from slavery was that it had a maximum term of 14 years – and in fact apprentices were generally freed a lot sooner. But this only makes it temporary rather than permanent slavery.
The first crown governor of Sierra Leone, Lt Thomas Perronet Thompson, turned up when this was already underway. He was an abolitionist protege of Wilberforce, chosen by him for the job, and he was appalled at what was happening. "These apprenticeships", he complained, "have after 16 years successful struggle at last introduced actual slavery into the colony".
He single-handedly abolished apprenticeship and freed the slaves. He filed scandalised reports to the colonial office. Wilberforce told him he was being rash and hasty, and he and his colleagues voted unanimously for his dismissal. Wilberforce advised him to go quietly for the sake of his career, which he did and indeed eventually became a general and MP.
What are we to make of it all? No interpretation that involves Wilberforce being corrupt, or insincere in his abolitionism, can possibly hold water. Vast amounts of his private letters and even privater journals are publicly available, and they reveal a man of extraordinary integrity and an implacable and lifelong (if slightly sentimental) hatred of slavery.
The key I think is that the apprenticeship system was explicitly authorised in the 1807 Abolition Act. Wilberforce told Thompson, "I wish I had time to go into particulars respecting the difficulties which forced us into acquiescing in the system of apprenticing". Which is tantalising, but also suggests that Wilberforce had made a political decision to support it as a government policy.
My theory is that Wilberforce and the Clapham sect believed that the Abolition Act would not get through the House of Lords without the apprenticeship clause, and once it was passed felt duty bound to support the system against Thompson's maverick actions.
But if so, and if Wilberforce was right that without apprenticeship the abolition bill would not have been passed, then it follows that he made the right choice to support it. Before abolition, 40,000 African people each year were being made slaves by the British. After abolition, several hundred of them a year were still ending up as slaves in Freetown.
It is a bitter irony, and a disappointment, but it does seem that Wilberforce was faced with a choice between two evils, and chose the less.
(5) Ellen Gibson Wilson, Thomas Clarkson (1989)
The five volumes which the Wilberforces published in 1838 vindicated Clarkson's worst fears that he would be forced to reply. How far the memoir was Christian, I must leave to others to decide. That it was unfair to Clarkson is not disputed. Where possible, the authors ignored Clarkson; where they could not they disparaged him. In the whole rambling work, using the thousands of documents available to them, they found no space for anything illustrating the mutual affection and regard between the two great men, or between Wilberforce and Clarkson's brother. They had room, however, to exploit two highly personal incidents, involving Clarkson's letters about his financial subscription and his plea for his brother's promotion. These were written when Clarkson was shattered in mind and body. The Wilberforce's use of them attracted almost universal condemnation at the time...
The problem raised by the Wilberforce Life was identified by Henry Robinson. Not one in a hundred readers of the Life would be able to compare its account of the abolition campaign with Clarkson's History, published 30 years before. The Life has been treated as an authoritative source for 150 years of histories and biographies. It is readily available and cannot be ignored because of the wealth of original material it contains. It has not always been read with the caution it deserves. That its treatment of Clarkson, in particular, a deservedly towering figure in the abolition struggle, is invalidated by untruths, omissions and misrepresentations of his motives and his achievements is not understood by later generations, unfamiliar with the jealousy that motivated the holy authors. When all the contemporary shouting had died away, the Life survived to take from Clarkson both his fame and his good name. It left us with the simplistic myth of Wilberforce and his evangelical warriors in a holy crusade.
(6) Robert Wilberforce and Samuel Wilberforce, letter to Thomas Clarkson (1786)
As it is now several years since the conclusion of all differences between us, and we can take a more dispassionate view than formerly of the circumstances of the case, we think ourselves bound to acknowledge that we were in the wrong in the manner in which we treated you in the memoir of our father.... we are conscious that too jealous a regard for what we thought our father's fame, led us to entertain an ungrounded prejudice against you and this led us into a tone of writing which we now acknowledge was practically unjust.