Quoting Trent W. Buck (trentbuck@gmail.com):
Are you sure about that?
I had a quick look and all I can find for the UK is conscience votes in 1976 (join the EEC?) and 2016 (leave the EU?).
It does say "cabinet", though, so maybe that doesn't apply to backbenchers?
To the best of my recollection, it's almost vanishingly rare for _any_ member of the Commons. Note that, when 21 Tory MPs failed to back BoJo on one of his very controversial Brexit votes[0], they were literally thrown out of the (increasingly ironically named) Conservative and Unionist Party, and half of those[1] currently face very daunting if not prohibitive electoral prospects in the impending snap election for the Westminster Parliament, because they cannot stand as Conservative candidates. It's rare enough that one of the characters in G&S's 'Iolanthe' (Private Willis, singing while on sentry duty in Palace Yard outside Westminster Hall) acidly observes about MPs: When in that House MPs divide, If they’ve a brain and cerebellum, too, They’ve got to leave that brain outside, And vote just as their leaders tell 'em to. [0] Including Sir Nicholas Soames, Winston Churchill's grandson. https://abcnews.go.com/International/churchills-grandson-20-mps-expelled-con... Sir Nicholas decided based in part on October's events that he will not run again. [1] Ten of the 21 were quietly readmitted at the end of October. https://www.forexlive.com/news/!/10-of-21-expelled-tories-have-been-readmitt... -- Cheers, "Maybe the law ain’t perfect, but it’s the only Rick Moen one we got, and without it we got nuthin'." rick@linuxmafia.com -- U.S. Deputy Marshal Bass Reeves, circa 1875 McQ! (4x80)