In 1780 Pitt was returned at Poole on a joint interest with Joseph Gulston, and according to Robinson’s 1780 survey ‘made professions of friendship to Lord North’. But on 23 Sept. he wrote to Lord Herbert:
Well ... we are now both in Parliament ... I long much to talk with you further on the subject. I believe we shall agree that it is better as well as more prudent not to appear to come with a predetermined intention of siding uniformly with one or the other set. Surely it is possible to act an upright, independent, and respectable part in Parliament yet I am told not. I hope you feel yourself bold enough to try it; be assured of one thing, that if a number, and even a very small number, fall into that channel they must acquire consideration, and collect a greater force daily. Consider maturely and then determine upon this matter.
Pitt himself consistently voted in opposition till the fall of North; voted for Shelburne’s peace preliminaries and for Pitt’s parliamentary reform proposals, 7 May 1783, but was absent on Fox’s East India bill. In his electoral survey of December 1783 Robinson noted against Poole: ‘Probably the old Members, but not certainly so; there may be a contest. Query, Mr. Pitt gone abroad.’
Pitt took an active interest in social conditions in his neighbourhood: established a cordage factory in the Isle of Purbeck, a hat factory in Dorchester gaol; attempted to interest his fellow landowners in the condition of the poor; and was one of the first promoters of Sunday schools. He died 29 Feb. 1836.