The Shadow Cabinet is a feature of the Westminster system of government. It consists of a senior group of opposition spokespeople who, under the leadership of the Leader of the Opposition, form an alternative cabinet to that of the government, and whose members shadow or mark each individual member of the Cabinet. Members of a shadow cabinet are often but not always appointed to a Cabinet post if and when their party gets into government. It is the Shadow Cabinet's responsibility to criticise the policies and actions of the government, as well as offering an alternative program.
In most countries, a member of the shadow cabinet is referred to as a Shadow Minister. In Canada, however, the term Opposition Critic is more common. In the United Kingdom's House of Lords and in New Zealand, the term "spokesperson" is used instead of "shadow".
The first shadow cabinet was instituted by UK leader of the opposition Hugh Gaitskell in 1951 to assist in opposing the policies of the government of Winston Churchill.
In the United Kingdom, Canada and New Zealand the major opposition party and specifically its shadow cabinet is called His or Her Majesty's Loyal Opposition. The adjective "loyal" is used because, while the role of the opposition is to oppose Her Majesty's Government, it does not dispute the sovereign's right to the throne and therefore the legitimacy of the government. However, in other countries that use the Westminster system, the opposition is known simply as The Parliamentary Opposition.
Some parliamentary parties, notably the Australian Labor Party, elect all the members of their shadow cabinets in a party room ballot, with the Leader of the Opposition then allocating portfolios to the Shadow Ministers. In other parliamentary parties, the membership and composition of the Shadow Cabinet is generally determined solely by the Leader of the Opposition.