The English Liberal Party in the 1820s was going through an interesting transition. Previously known as the “Whigs,” the party ultimately began its transition to “Liberalism” after a period following the French Revolution. Though the Liberal Party (including its predecessor Whig Party) held various views throughout its history, all Liberals had a singular conviction that united all of them: that progress only came about “in the free exercise of individual energy.” The Party’s mission, then, was to create an environment in society in which individual energy could thrive. This was the school of thought of many of JS Mill’s peers and father’s peers. Mill was visiting France in 1821 when he stayed at the home of M. Say and was introduced to this concept of Liberalism.

Sources: 

Britannica, T. Editors of Encyclopedia. "Whig and Tory." Encyclopedia Britannica, May 18, 2020. https://www.britannica.com/topic/Whig-Party-England. 

Webb, P. David. "Liberal Party." Encyclopedia Britannica, March 15, 2018. https://www.britannica.com/topic/Liberal-Party-political-party-United-Kingdom.