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An oddity today: MPs who have voluntarily resigned their seats and then come back for a *different* seat in the same Parliament. Quite a lot of "well, I'd just prefer to sit for X" - hard to imagine that now. https://w.wiki/mWQ
(this doesn't include any who were ousted by election petitions, or returned for two seats and picked their favourite)
Filtering to just those with a two-month gap or less and there's a really apparent trend of "switch to a county/university seat, they're more prestigious", though it drops off a bit in the more recent years https://w.wiki/mWW
The omission of cases involving election petitions means it doesn't cover Luke White, who was elected for Clare 1859, overturned 1860, elected for Longford 1861, resigned 1862, and came back for Kidderminster.
Another oddity with three in the same term was William Dundas, who was elected for Sutherland in 1807, resigned 1808, came back for Elgin 1810, got made a minister in 1812, and took the opportunity of the by-election to switch to a conveniently vacated seat in Edinburgh.
(Mostly missing pre-1820 constituencies & pre-1832 reasons for departure so not sure how many similar examples of this there will turn out to be, but I suspect it will be increasingly common...)
Last modern examples of voluntarily switching seat for reasons of personal preference seem to be William Redmond in 1918 and Austen Chamberlain in 1914, both times to take up the seat held by their recently deceased father.
Checking the numbers - of 36 changes with <2mo gap 1832-1900, 24 "trade up" from a borough to a county seat; only one goes the other way. 6 stay in the same type of seat, and five go from a county or borough up to a university seat.
Excellent thread on the reasons why this happened https://twitter.com/TheVictCommons/status/1327613673754472454
