@Independent: Already the shortest-serving PM in history, Liz Truss has now also become the first former leader since 1935 to lose their seat https://t.co/WHncZ3CeoP
Brown was Labour. But yes, sort of.
May (as of today I think) and Cameron (as of about 12 months ago) are both peers, so they sit in the Lords, but Truss has been kicked and Johnson quit.