He was involved in several slave trading companies and was known for his knowledge of the African coast derived from his many journeys dating back to 1776.
When in 1788, the British government launched an inquiry into the slave trade, following public pressure from abolitionists, Penny was chosen to represent the views of slavers.
Sanderson, he was a "man of considerable stature in the town, highly regarded by his fellow merchants, his forthright views on the slave trade must have brought him to their notice as a likely delegate".
[3] In the possible evidence he gave the British Government, Penny claimed that "he found himself impelled, both by humanity and interest, to pay every possible attention both to the preservation of the crew and the slaves.
If the Weather is sultry, and there appears the least Perspiration upon their Skins, when they come upon Deck, there are Two Men attending with Cloths to rub them perfectly dry, and another to give them a little Cordial....