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Prerogative (“prae” + “rogare”) literally means ‘before asking [the people]‘. However, we usually consider its definition to mean powers not shared with others. It is often thought that the Queen is the only person who has prerogative powers, however most central governmental operation is carried out under the virtue of the prerogative powers. Dicey said that prerogative powers are:
The residue of discretionary or arbitrary authority which at any given time is legally left in the hands of the Crown.
Properties of prerogative powers
Prerogative powers are exercised under convention and were antecedent to statutory authority. They can be exercised by the monarch on the advice of the Government, or by ministers in their own right. Note the first point here: the monarch is constitutionally bound to follow Government’s advice.
Limiting prerogative powers
There is no exhaustive list of prerogative powers, nor can new powers be created. Powers can only be eroded, as they have been over the past 350 years.
The Bill of Rights 1689 was the first win of the rule of law against the prerogative. This statute limited the powers of the monarch. Coke CJ in the Case of Proclamations ruled that it is for the judiciary to decide whether a certain prerogative power exists and more recently, in Attorney General v De Keyser’s Royal Hotel , it was confirmed that the prerogative’s is inferior to the legislature.
In Council of Civil Service Unions v Minister for Civil Service  – ‘the GCHQ case’ – the prerogative was victorious over civil servant’s rights to join trade unions and in R v Secretary of State for Foreign Affairs ex parte Everett , it was ruled that actions taken under the crown can be judicially reviewed.
Ultimately, Parliament is now supreme over the historic prerogative powers and can erode if it so wishes.
Today, the Queen has many duties still remaining which she exercises under the prerogative. She has the power to appoint any person the Prime Minister; she can dissolve parliament; she can dismiss ministers and has many relatively undefined emergency prerogative powers.
The Queen actually has a very long list of powers according to Allen; the above list is only a few of them.
Next: Parliamentary privilege