Under a Westminster system of governance, these powers are vested nominally in HM Queen Elizabeth II, Queen of Barbados (represented by the Governor-General), but are exercised in practice by a Cabinet of Ministers, presided over by the Prime Minister. The Prime Minister is formally appointed by the Governor-General: the Governor-General must appoint as Prime Minister someone who can control a majority of votes in the House of Assembly. In practice, this is normally the leader of the largest political party or coalition in the house. If there is no clear majority in the House of Assembly, however, the Governor-General's role becomes more important: he or she must assume the role of arbitrator and open negotiations with the leaders of the various political parties, in the hope of finding someone whom a majority will accept as Prime Minister. In the event of that failing to take place, the Governor-General must dissolve the House of Assembly and call an early election.
The Cabinet system of government was implemented in Barbados in 1 February 1954 after attainment of full self-government earlier. Prior to an official Cabinet, the role was fulfilled by the colonial era Executive Council on the island. Under the Constitution of Barbados, Cabinet is not prescribed a maximum number Cabinet of Ministers however, it must have no fewer than five members. The first Cabinet was led by Premier Sir Grantley Herbert Adams. The four other Ministers were:
^Cabinet of Barbados' advice for grant of Knighthood to G.G. Belgrove, Issue number: 60166, Page number: 10993, Friday 8 June 2012, The Honours and Awards Central Chancery of the Orders, The London Gazette: THE QUEEN has been graciously pleased, on the advice of Her Majesty’s Barbados Ministers, to give orders for the following appointment to the Most Distinguished Order of Saint Michael and Saint George: G.C.M.G. - To be an Ordinary Member of the First Class, or Knight Grand Cross, of the said Most Distinguished Order: His Excellency Elliott Fitzroy BELGRAVE, Governor-General of Barbados.