Anthony Eden (1955–57)
Harold Macmillan (1957–63)
Alec Douglas-Home (1963–64)
Harold Wilson (1964–70)
Edward Heath (1970–74)
Harold Wilson (1974–76)
James Callaghan (1976–79)
Margaret Thatcher (1979–90)
John Major (1990–97)
Tony Blair (1997–07)
Gordon Brown (2007–10)
David Cameron (2010–16)
Theresa May (2016–19)
Boris Johnson (2019–22)
Liz Truss (2022 (two days ago) - current)
Quite the reign! Can't help but feel a bit sad really.
Downside: lots of bizarre complexities, bits of dead code, stuff that works as long as nobody touches it etc. Upsides: it's really stable.