No PM since Thatcher has been given a peerage, though I believe Major through Brown turned them down, unsure about Cameron, and May is still an MP. Historically

No PM since Thatcher has been given a peerage, though I believe Major through Brown turned them down, unsure about Cameron, and May is still an MP. Historically they would be given an hereditary earldom, this switched to life peerages under Douglas-Home (who gave up his hereditary earldom to become Prime Minister). Churchill was famously offered a dukedom by both The Queen and George VI, turning down both.