In the absence of a comprehensive and reliable source, for party and factional alignments in this period, no attempt is made to define them in this article.
The House of Commons: 1790–1820 provides some guidance to the complex and shifting political relationships, but it is significant that the compilers of that work make no attempt to produce a definitive list of each members allegiances.
Where the cause of by-election is given as "resignation", this indicates that the incumbent was appointed on his own request to an "office of profit under the Crown".
These appointments are made as a constitutional device for leaving the House of Commons, whose Members are not permitted to resign.
The c/u column denotes whether the by-election was a contested poll or an unopposed return.