A lady on horseback rides between Pitt and Wilberforce mounted on asses. The ass (left) on the lady's right is galloping, its rider (Wilberforce) waves his hat triumphantly towards Pitt whose ass refuses to move. A man standing behind it (right) by a milestone inscribed 'Wimbledon Common', is about to kick the ass violently. The lady, whose horse is restive, raises her riding-switch to beat Pitt's ass.
Grego, Joseph. "Rowlandson the caricaturist; a selection from his works with anecdotal descriptions of his famous caricatures, in two volumes." London: Chatto and Windus, 1880