When his father was elevated to the House of Lords in 1786, he had Petty, now with the courtesy title of Earl Wycombe, returned to the Commons from his old seat, Chipping Wycombe. While he urged his son to "take a manly part in politics, be it aristocrat or democrat", "Wycombe" was frustrated by his continued dependence on his father's favour. He befriended Jeremy Bentham who, in 1798, described Wycombe as a man who had "begun to feel his ground by taking some novel propositions". He escaped his father's supervision by travelling in the winter of 1789–90 to the continent, where he experienced the first reverberations of the French Revolution. In 1791, he visited the new American republic and then journeyed to Paris where he witnessed the humiliation of the King following his Flight to Varennes.
