New Zealand Law Society - Lord Mansfield: Justice in the Age of Reason

Lord Mansfield: Justice in the Age of Reason

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Reviewed by Peter Twist 

Norman S Poser, Professor Emeritus at Brooklyn Law School, has written the first full length biography in modern times of the life of William Murray, the first Earl of Mansfield (1705-1793), who sat as Lord Chief Justice of the Court of King’s Bench from 1756 until 1788.

Many books on the lives of judges are dull, but Poser’s book is not one of them. Comprehensive and well-researched, his book is beautifully written with a rhythmic pace and racy style that brings to life one of eighteenth century England’s outstanding figures, not just in the legal profession but politically and socially.

Following the preface, the book contains an excellent chronology with comparative dates of major historical events, events in Mansfield’s life, and his important legal decisions. The illustrations include portraits of Mansfield and other historical figures, as well as the portrait by Johan Zoffany of Mansfield’s grandnieces, Dido Elizabeth Belle1 and Lady Elizabeth Murray,2 which is famous for being the first known portrait to show both black and white subjects as equals.3

The first 180 pages in Part One (“Becoming Lord Mansfield”) are devoted to the background, skills and motivations of a man who was to become one of the western world’s preeminent legal thinkers, whose legal decisions are still respected and cited today.4 In Part Two (“Justice in the Age of Reason”) the book extensively discusses Lord Mansfield’s legal decisions under chapter headings, such as Slavery and the Somerset Case (Ch 17), Women and Marriage (Ch 20), and Religious Freedom (Ch 21); these legal decisions can be understood more clearly by the author’s earlier treatment of William Murray the man.

Taint of Jacobitism

William Murray was the fourth son of David Murray, Viscount Stormont, born at the Palace of Scone, near Perth, Scotland. Although William was a member of the Scottish aristocracy, his family was not wealthy and the Scottish nobles were not trusted by the English because of their support of the Stuart cause in the 1715 rebellion, after which William’s father and his brother David were fined and imprisoned.

No one would have predicted that, when young Murray arrived in London in 1718 after having travelled alone by pony from Perthshire, he would one day rise to the position of Lord Chief Justice of the Court of King’s Bench. Murray attended Westminster School5 and Christ Church, Oxford, where he excelled in classics and became an eloquent speaker, though he never entirely lost his Scottish accent. Despite being the chosen educational institutions for the sons of the establishment, both Westminster and Christ Church were hotbeds of Jacobitism6 in early eighteenth century England, where toasts were drunk to the Old Pretender.7 We soon learn that Murray had a guilty secret: in 1725, while travelling in France as a 20-year-old, he wrote to his brother-in-law, John Hay, to offer his loyalty and services to the Old Pretender; he must have feared all his life that this correspondence would be discovered and he might be indicted for high treason, especially when, as Solicitor-General in 1745-1746, he assiduously prosecuted the rebel lords in the Jacobite rebellion for high treason, or when his arch-enemy William Pitt the Elder made innuendoes in Parliament that he secretly harboured Jacobite sympathies.

Rising lawyer and politician

After obtaining his BA at Oxford University in 1727, Murray began studying law at Lincoln’s Inn, mainly by private study and observing court proceedings, since legal education was not formalised at the time, after which he was admitted in 1730. At first, business came slowly to Murray, but he soon began to build up a considerable practice arguing Scottish appeals in the House of Lords. After successfully representing the provost of Edinburgh before the bar of the House of Commons in order to defeat a harsh bill, his reputation as a gifted advocate was established and he began getting a flow of lucrative cases in the Court of Chancery.

In 1738 he married Lady Elizabeth Finch, sister of the Earl of Winchilsea and granddaughter of the Earl of Nottingham, a former Lord Chancellor. Although Lady Betty was good looking, she was 34 at the time of her marriage, a year older than Murray, in an era when the average age of marriage by aristocratic noblewomen was under 25. Poser speculates that, despite having had other opportunities to marry, Lady Betty was willing to wait for an exceptional man like Murray, who was free of the common vices of eighteenth century noblemen: drunkenness, sexual promiscuity and gambling. Although the marriage was childless, it was a happy one and lasted 46 years until Lady Betty’s death in 1784. Murray held his intelligent and sociable wife in high esteem and must have recognised his good fortune in making such a choice.

Although his marriage into the prominent Finch family would have assisted his entry into politics, the principal factor that launched Murray on his political career was his close relationship with the Duke of Newcastle, the leader of the Whig government in the House of Lords, who was chiefly responsible for Murray’s election to Parliament and his appointment as Solicitor-General in 1742. At the same time Murray took silk to become a King’s Counsel. Murray had been Newcastle’s private adviser and he continued to act as such after he entered Parliament.

As Solicitor-General, Murray provided legal opinions to the government, drafted legislation, prosecuted major crimes, such as treason, and represented the government in law suits, all while he continued to conduct his own private practice of law. In Parliament, he still gave eloquent speeches and debated with his rival, Pitt the Elder.8

In 1754, when Ryder was appointed the Lord Chief Justice of the Court of King’s Bench, Murray succeeded him as Attorney-General.

Lord Chief Justice

After Ryder’s death, Murray was appointed Lord Chief Justice of the Court of King’s Bench in 1756 and raised to the peerage as Baron Mansfield.

The canny Murray refused the appointment until King George III agreed to grant him a peerage. In 1776 he was created the Earl of Mansfield.

Mansfield was a follower of John Locke and believed in political freedom, religious toleration, and economic individualism. One of his great achievements was assimilating mercantile custom into the common law whereby he constructed a settled system of principles and rules in commercial law that could be relied upon by merchants and lawyers. He also pioneered the development of the principle of unjust enrichment.

Mansfield sought to limit the restrictions placed on Catholics and Protestant dissenters. On the other hand, his liberal leanings did not extend to freedom of the press and he went to great lengths to punish sedition. He also showed no clemency to forgers, whom he viewed as disruptive of commercial life, and he frequently prevailed upon the King not to commute death sentences handed out to them.

During the American Revolution, Mansfield influenced Britain’s policy in the war by advising the King to be harsh on the American colonists, one of the few times his advice was erroneous. At the time, the doctrine of separation of powers had not developed to the extent it has today, and modern jurists will be astonished to see that an eighteenth century Chief Justice might sit in court in the morning, speak in Parliament in the afternoon, and advise the King on foreign policy in the evening.


Although Mansfield considered slavery odious, he was reluctant to make any decision on the status of slaves that might prejudice Britain’s commercial interests in the West Indies and the American colonies.

In the Somerset case9 a slave owner had abducted an escaped slave and held him onboard a ship awaiting transportation to Jamaica to be sold in the slave market there. Although Mansfield upheld a writ of habeas corpus preventing the slave owner from keeping Somerset in captivity and taking him out of the country against his will, Poser argues convincingly that Mansfield’s decision did not hold slavery to be illegal.10

Nevertheless, many people believed that Mansfield had put an end to slavery and the decision gave the abolitionists the impetus they needed to lobby Parliament to outlaw the slave trade in 1807 and eventually to abolish slavery altogether throughout the British Empire in 1834.

Gordon Riots

In 1780 one of the worst disturbances in London’s history occurred, the week-long anti-Catholic Gordon riots. As a Catholic sympathiser, Mansfield was a target and his home in Bloomsbury Square was burned by rioters with the loss of most of his books and papers, which was an incalculable loss to history as well as his family. Two of the offenders were later hanged facing the shell that had been his home.

Later years

After Mansfield’s wife died in 1784, his grandniece Dido, who had always lived at his country home Kenwood at Hampstead with him and Lady Betty, cared for him in his old age, as if he were her father. In 1786 Mansfield ceased to sit in court, but continued to act as Lord Chief Justice until 1788 when he resigned. Mansfield regarded Dido highly and she was a beneficiary in his will when he died in 1793.


Not only is Poser’s book the definitive study of Mansfield’s life, but it is a looking glass into eighteenth century society and politics leading to an understanding of the development of our parliamentary democracy. It is hard to imagine that a better book on Mansfield could have been written.

Lord Mansfield: Justice in the Age of Reason, McGill-Queen’s University Press, May 2014, 978-0-773541-83-2, 560 pages, £25.99.

Peter Twist is an Auckland barrister who specialises in land law. He is a contributor to Hinde McMorland & Sim Land Law in New Zealand and Sim’s Court Practice.


1. Dido was the daughter of John Lindsay, Mansfield’s naval-officer nephew, and a West Indian slave.

2. Lady Elizabeth was the daughter of Viscount Stormont, Mansfield’s nephew.

3. For those who are interested, Mansfield’s fatherly relationship with his grandniece Dido is portrayed in the delightful 2013 film Belle, which stars Tom Wilkinson as Mansfield and Gugu Mbatha-Raw as Dido. Although Wilkinson gives a strongly believable performance as Mansfield, the film is fiction and the script is highly idealised, wrongly portraying Dido as influencing Mansfield on slavery issues in the Zong decision.

4. The United States Supreme Court has cited his decisions over 330 times.

5. In early eighteenth century England, Westminster School, not Eton College, was the preferred training ground of the élite.

6. The Jacobites were the supporters of deposed King James II and his descendants, who continued to claim the throne.

7. James Francis Edward Stuart, the son of James II, who claimed the thrones of England and Scotland after his deposed father died in 1701. The unsuccessful 1715 rebellion was raised in his name. His son, Charles Edward Stuart, the New Pretender, who is better known to posterity by the sobriquet “Bonnie Prince Charlie”, led the 1745 rebellion, which was defeated at the Battle of Culloden in 1746.

8. In 1748 he successfully defended the unpalatable Treaty of Aix-la-Chapelle made at the end of the War of the Austrian Succession on behalf of the government in the House of Commons.

9. Somerset v Stewart (1772) Lofft 1; 98 ER 499.

10. In the infamous case of the slave ship the Zong (reported in Gregson v Gilbert (1783) 3 Dougl 233; 99 ER 629), the ship owner had brought a lawsuit against its insurers for loss of cargo after it had thrown slaves overboard because they claimed that they had run out of water. Mansfield simply rejected the ship owners’ claim on the ground that it had not been necessary to throw the slaves overboard because it was possible that there was water available for the slaves.

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