Most Speakers have been senior backbenchers of the party holding office at the start of a new Parliament, or at the time of the death or resignation of an incumbent Speaker. Five Speakers have been former government ministers: William Watt, Littleton Groom, Archie Cameron, Ian Sinclair and Bronwyn Bishop; one a former Parliamentary Secretary: Stephen Martin; and one both a former minister and a former Leader of the Opposition: Billy Snedden. Two were former state premiers: Holder and Watt. There is no convention in Australia that Speakers should resign from Parliament at the end of their term; two Speakers have become Cabinet ministers after having been Speaker: Norman Makin and Gordon Scholes.