“…Consistent with developments in other parliamentary democracies (LeDuc, 2001;Kenig, 2009a: Kenig, 2009bCross and Blais, 2012a;Cross and Blais, 2012b;Pilet and Cross, 2014;Cross and Pilet, 2015) they have expanded their leadership selectorates beyond parliamentary elites to include party members (Quinn, 2010), delegates and members of affiliated organizations, particularly trade unions (Drucker, 1981;Quinn, 2004;Wickham-Jones, 2014) and even latterly, in the case of the Labour Party, their affiliated and registered supporters (Quinn, 2015;Dorey and Denham, 2016). Building on a recent comparative study of party leadership selection in the five principal Anglophone ('Westminster') parliamentary democracies (Cross and Blais, 2012a), this article first sets out its theoretical framework that purports to explain why the major parties in three of those countries, including Britain, have adopted such reform.…”