IT IS estimated that there were between 3,000 and 5,000 black people living in London in the 18th century, an inevitable result of Britain’s involvement in the slave trade.

One of them was Francis Barber, a former slave who became the servant of Dr Samuel Johnson, the compiler of the English dictionary.

Although Barber lived with Johnson for more than 30 years and became his heir, little is known about him.

He has now been rescued from obscurity by Michael Bundock’s compelling biography, which places his life firmly in the context of black history.

“Francis Barber’s story is fascinating and I felt it was important to tell it,” he says.

“It is also a reminder that there was a significant black community in 18th-century London and that slavery wasn’t something that happened somewhere else.”

But at the heart of the story is the extraordinary friendship that existed between servant and famed man of letters at a time of heightened hostility towards black people in the face of the increasing legal and moral challenges that would lead to the abolition of the slave trade a few decades later.

Born on a sugar plantation in Jamaica, Barber was brought to England by his owner in 1750 and joined Johnson’s household off Fleet Street in London aged 10. He would live there almost continuously until Johnson’s death in 1784, by which time his wife and three children were also part of the set-up.

Notoriously eccentric, Johnson scandalised society by what was considered his liberal treatment of “Frank” over the years, giving him light duties and even allowing him to bring his black friends to the house. When he died, Johnson caused further upset by leaving Barber the bulk of his estate.

Childless and given to bouts of melancholy, Johnson also had much to gain from Barber’s company, says Bundock, a lawyer whose interest in Barber emerged from his role as director of Dr Johnson’s House Trust. “Barber looked upon Johnson as a father figure but it was a two-way relationship that underwent role reversal over time. When Johnson fell ill Barber and his family looked after him. They both brought something to one another.”

Johnson’s affection for Barber was also framed by his strong sense of Christian duty and his aversion to slavery.

“Johnson was quite clear in his approach to slavery and on a number of occasions he spoke and wrote publicly against it,” Bundock explains. “He certainly did not regard Barber as a slave, while Barber thought of himself as a free man.”

Indeed, Barber felt free enough to walk out of Johnson’s employ when he was 14 and work for an apothecary in Cheapside. Later, like a wayward son, he ran off to sea during the seven years’ war, much to Johnson’s distress.

But how to write a book about someone whose written account of himself amounts to no more than the most basic of details?

Bundock did so by trawling through the archives as well as literature and press reports of the day in which Barber, thanks to his Johnson connections, makes walk-on appearances.

While these offer a view of how others regarded him, we inevitably have little idea of how he regarded the world or his position in it. Although richly researched, the book is a bit like a party in which the guest of honour has failed to show up.

“His voice does not come out,” acknowledges Bundock. “You have to work around this lack of a voice and sometimes make suppositions.”

Frustratingly, it transpires towards the end of the book that the striking cover image (above) which we have clung on to in the absence of a substantial personality is probably not of Barber after all.

“I don’t think it matters very much,” insists Michael. “The portrait can be taken almost as a symbol of the black community at the time, one that Barber was very much part of.”

• The Fortunes of Francis Barber: The True Story of the Jamaican Slave Who Became Samuel Johnson’s Heir, Yale University Press, £20. This article first appeared in the Camden New Journal.