Thomas was born on 28 March 1760 at Wisbech in Cambridgeshire, son of the Revd. John Clarkson (d.1766) and Anne (Ward). He was educated at his father's school and then went to school in London and later to St John's College, Cambridge. His brother John (1764-1828) joined the Royal Navy and was later Governor of Sierra Leone. An anti-slavery movement had been started by the Quakers and a formal committee, which included Thomas, was set up in 1787 to bring about the abolition of the slave trade. He laboured tirelessly in this cause, working closely with William Wilberforce, but the act abolishing the trade was not passed until 1807. Not until 1833 was slavery abolished throughout the British Empire. Thomas married Catherine Buck (d.1856) but their only child Thomas died before his father. He died in 1846 and was buried at St Mary's church, Playford, near Ispwich, in Suffolk. A memorial of green Cumbrian slate was unveiled for him in the Abbey on 26 September 1996, being placed between the statues of Wilberforce and Stamford Raffles in the north choir aisle. The inscription reads "a friend to slaves THOMAS CLARKSON b.Wisbech 1760-1846 d.Playford".

A photograph of the stone can be purchased from Westminster Abbey Library.

Further reading:
Further reading: "Thomas Clarkson, a biography" by Ellen Gibson Wilson (1989)
"Oxford Dictionary of National Biography" 2004