In 1782 Henry Thornton had been urged to seek a seat in Parliament, and applied to contest one of the two seats for Hull. He soon withdrew on a point of principle, after learning that it was local custom to pay each voter two guineas in order to secure their vote. In September the same year Thornton was elected as member for Southwark, London. Despite lacking popular appeal, and refusing to bribe voters in a similar way to those of Hull, he became respected as a man of morals and integrity.