 He was also a Captain in the Ayr yeomanry from 1803, promoted to Major in 1815 and becoming the Lieutenant-Colonel Commandant in 1816.Boswell bought his entry to the House of Commons in 1816, paying Paul Treby who controlled one seat in the borough of Plympton Erle in Devon.In politics he was a staunch Tory, generally voting with the Government of the day; however, he developed a grudge against the ministers personally and against Prime Minister Lord Liverpool in particular.