Lord Mansfield (1705-1793) was never really a people’s hero: in 1780 rioters enraged by his tolerance of Catholics razed his Bloomsbury home to the ground. He also courted unpopularity by prosecuting the scurrilous journalist John Wilkes, whose statue now stands just off Chancery Lane.

Mansfield’s monuments are a tomb in Westminster Abbey, a Hampstead mansion acquired on the proceeds of decades of coining it as solicitor-general and lord chief justice (now magnificently restored by English Heritage) – and of course his jurisprudence, with decisions ranging over topics from intellectual property, to gambling, to press freedom.

And, most famously, slavery, in the 1772 Somerset judgment.

In this thorough but highly readable biography, Norman Poser, professor emeritus at Brooklyn Law School, tackles both the life and legacy of this 18th-century giant. The book also has the luck of good timing: it coincides with the release of the film Belle, about Mansfield’s relationship with his ‘mulatto’ niece at a time of high controversy over the legal status of slavery.  

According to Poser, Mansfield was ‘reluctant to make any decision that would call into question the legality of the slave trade or slavery’. The Somerset case was forced upon him: it concerned a writ of habeas corpus against a merchant, Charles Stewart, on behalf of an escaped slave, James Somerset.

Mansfield’s initial solution was that Somerset’s abolitionist protectors buy him and set him free. But both abolitionists and slavers wanted a test case giving him no alternative but to rule on the narrow question of whether colonial slavery laws could be enforced in England.

His judgment to a packed courtroom has gone down as marking the beginning of the end of slavery: he ruled that the state of slavery ‘is so odious, that nothing can be suffered to support it, but positive law’. No such law being in existence, ‘the black must be discharged’. However, Poser points out that, contrary to abolitionists’ hopes, the ruling did not outlaw slavery in England, only give notice that English courts would not enforce it.

And 11 years after Somerset, Mansfield sat in judgment in another slavery case. The insurer of the slave ship Zong had refused to pay for 150 slaves thrown overboard on passage. The shipowner sued, and a jury sided with him on the grounds that loss was caused by the normal perils of the sea.

On appeal, Mansfield ordered a new trial because the shipowner had not demonstrated that it was necessary to throw the slaves overboard. Poser notes: ‘Nowhere in his short opinion was there any suggestion that the captain and crew of the Zong were murderers.’

Hollywood film leads mostly don’t behave like that. But Hollywood leads don’t make great judges.

Author: Norman S Poser

£25.99, McGill-Queen’s University Press

Michael Cross is Gazette news editor