Born in Bristol, the son of a physician who died at sea. After attending Colston's charity school, in 1725 he went to sea in a merchantman trading between England and the West Indies and was later press-ganged into the navy. He spent eleven years at sea and saw not only war service but much cruelty associated with life at sea before being discharged in 1736. He first came in touch with John Wesley in 1740 when he was persuaded by Charles Caspar Graves to hear him preach in Short's Gardens and the Foundery, London. In 1744 he took over the Foundery charity school. Moved by Wesley's sermon on 'I was sick and in prison and ye visited me not,' he began visiting the prisoners in Newgate, accompanying many of them to the gallows. The rest of his life was given to this ministry, through which he saw many prisoners reformed. In Wesley's words, 'No man for this hundred years has been so successful in that melancholy office.'