Here's a provisional chart illustrating the turnout at each British election from 1885 to the present, including turnouts in each constituent country as well as the constituencies with the highest & lowest turnouts.
I should note that the table is not quite complete: I haven't yet been able to square the electorate figures for 1918 and 1987-1997 completely, nor have I yet found estimates for numbers of electors voting (as opposed to votes cast) in the dual-member Cambridge University, Cork City & Dublin University constituencies prior to 1918. Will of course update the table when these deficiencies have been rectified, but the overall national figures should remain largely the same as they are now.
Never realised that Wales used to have the highest turnout of the four nations. Must’ve been a time when the industrial cities had relatively high turnouts - unlike what we see today.
