Captain Kimber was arrested within days of Wilberforce's denunciation of him in the Commons. The arrest surprised members of the Trade, who believed Wilberforce or the Abolition Committee was behind it. In fact the prosecution was public not private, noteworthy because the Board of Admiralty, who were responsible for murder on the high seas, had resisted calls for a criminal prosecution in the Zong affair some nine years earlier. Prosecutions for murdering slaves were not unknown in Admiralty courts, but they were extremely rare. As I have already mentioned, the only instance I have discovered at the Old Bailey itself occurred in 1759, when William Lugen, the captain of another Bristol ship, the Hope, was indicted for throwing a four-month-old baby overboard. He was acquitted because in the jury's view the child had the bloody flux [dysentery] and had lost her mother. She was dying anyway, so the jurymen thought; in the language of insurance, from ‘natural causes’.

Precisely who pushed for a state prosecution is not at all clear. I have found no hint in the Pitt papers or the Admiralty records, whether those of the Board or the Admiralty Solicitor, or in the letters to the Admiralty from the Privy Council and the Secretary of State. What I do know is that by virtue of a warrant issued by the High Court of Admiralty, Bow Street runners Thomas Carpmeal and John Miller were dispatched to Bristol to arrest Captain Kimber on Friday, 6 April 1792. They called at his house at 27 Redcross Street, but Kimber seems to have made himself scarce. The runners could not find him all day Saturday, and so they left a message on Sunday morning that they wished to talk to him about shipping some goods and would meet him at the Exchange between 12 and 1 pm. Kimber was likely in hiding, and may only have agreed to turn himself in at the behest of some Bristol merchants. When he arrived at the Exchange, the runners took him into custody. By the time the runners left the Bush Tavern in Corn Street for London, word had circulated that Kimber had been arrested and the streets were crowded.