| Constituency | Dates |
|---|---|
| Abingdon | [22 May 1689] |
Commr. for assessment, Berks. 1677 – 80, 1689 – 90; freeman, Abingdon Sept. 1688; j.p. Berks. by 1701–d.2Abingdon bor. mins. 2, p. 54.
A strong Whig like his father and his brother-in-law John Trenchard, Southby came under suspicion at the time of the Rye House Plot. He was apparently a Whig collaborator, the King’s electoral agents reporting in 1688 that he was proposed by the Presbyterian party as candidate for Abingdon, ten miles from his home. He was returned at a by-election in May 1689, but left no trace on the records of the Convention. He was unseated in favour of Sir John Stonhouse on 8 Jan. 1690, and did not contest the constituency again, though he had hopes of election for Oxford University in 1695. He was buried at Buckland on 1 Apr. 1741, the last of his family to sit in Parliament.3CSP Dom. July-Sept. 1683, p. 227; CJ, x. 126, 162; 277-8, 327; HMC Downshire, i. 563; Cherry, 2, p. 47.
