Numbers and proportions are as they were directly after the relevant election and do not take into account by-elections, defections, or other changes in membership. Instead, women who were initially by-elected to their seats and later successful in holding them at a subsequent general election are counted as having won the latter to serve full terms, if completed. Parties whose MPs have taken or took the whip from one of the major parties have been included in the Conservatives' or Labour's totals.