Solomon Northup was born a free man in Saratoga Springs, New York, in 1808. He lived as such until 1841 when, attracted by a job offer, he travelled to Washington, DC, where he was drugged and sold into slavery by his supposed employers.

Northup was enslaved for twelve years before he regained his freedom and returned to New York. There, he became an advocate for abolitionism and in the 1860s began helping fugitive slaves via the Underground Railroad.

Northup is believed to have died between 1863 and 1875, but both the date and circumstances of his death are unknown.

Sojourner Truth (c.1797 - 1883) was born into slavery in New York State. In 1826, she escaped with her young daughter, leaving two of her other children behind. When her son was later illegally sold to a slave owner in Alabama she sued for his return, becoming one of the first black women to successfully challenge a white man in an American court. She spent the rest of her life campaigning for abolition, equal rights and universal suffrage, and found fame as a reformer and public speaker. Her memoir, The Narrative of Sojourner Truth, is published in Penguin Classics.

Frederick Douglass was born into slavery in Maryland, 1818. He was separated from his mother as a baby and lived with his grandmother up to the age of eight, when he was sent to live as a house servant, a field hand and then a ship caulker. He escaped to New York in 1838 and seven years later published Narrative of the Life of Frederick Douglass, an autobiography of his life as a slave, which became an instant bestseller.

Douglass rose to fame as a powerful orator and spent the rest of his life campaigning for equality. He became a national leader of the abolitionist movement, a consultant to Abraham Lincoln in the civil rights movement and a passionate supporter of the women’s rights movement. He died in 1895.

Stephen Smith, a veteran of over a thousand armed operations during his twenty-two years with the Metropolitan Police specialist firearms command, was born in south London in 1960. He joined the Met at nineteen and after twelve years in uniform passed selection for PT17, the Mets firearms unit, where he was selected to work on the specialist firearms teams, experiencing first-hand the explosive and controversial world of police firearms operations.