Falconbridge had taken part in four voyages on slave ships before he met the anti-slavery campaigner Thomas Clarkson following which he became a member of the Anti-Slavery Society. Clarkson was the author of a pamphlet entitled "A Summary View of the Slave Trade and of the Probable Consequences of Its Abolition", published in 1787. Clarkson had a high regard for Falconbridge who on more than one occasion acted as his personal armed bodyguard whilst he gathered evidence against the slave trade.