Under the monarchial constitution of the United Kingdom, the majority of prerogative powers are nowadays exercised by the government of the day or the judiciary in the name of the Crown. Two principal authoritative definitions are relied on by the courts today; that of Sir William Blackstone and that of Professor A. V. Dicey.From this we can see that the prerogative is inherent in and peculiar to the Crown, prerogatives are recognized by the courts, the rights and powers are residual: they cover areas over which Parliament has not enacted statutes and they can be limited by Parliament and the prerogative legitimises executive actions without the need for an Act of Parliament. The definitions give rise to a number of questions.

On the one hand, the executive has too much power to exercise in the name of the Crown which leads to a problem of abuse of power.On the other hand, it makes the scope of the prerogative power ambiguous and it seems that the prerogative power is somehow in conflict and inconsistence with Acts of Parliament. Therefore, it is essential for the courts and Parliament to prevent the abuse of such powers through case law and enactment. Since 1688, majority of the prerogative power has transferred to the executive.

There were number of cases that the defendants sought for jurisdiction after the executive exercised the prerogative power in areas where no enacted statutes protected.Traditionally, as noted above, the courts had jurisdiction to decide whether a prerogative existed and, if so, its scope. Judges would not examine the merits of the exercise of the prerogative. In the case of Attorney General v de Keyser’s Royal Hotel Ltd (1920), the House of Lords ruled that where an Act of Parliament covers the same scope as a prerogative, the Act of Parliament prevails and the prerogative – if not expressly abolished – is placed is abeyance (effectively suspended).Accordingly, the government could not choose to use the prerogative to award a lesser amount of compensation for occupation of property in wartime than the amount provided for under the Defence of the Realm Acts. In Laker Airways v Department of Trade (1977), it was held that a prerogative – in this case the treaty-making power – could not be used to defeat a right granted under an Act of Parliament.

In R v Secretary of State for the Home Department ex parte Northumbria Police Authority (1985), theCourt of Appeal ruled that the Home Secretary had the power to issue weaponry to police forces under the prerogative. This applied even though no direct authority could be found for there being a prerogative ‘to keep the peace’ as the Home Secretary claimed. This was notwithstanding the Police Act 1964 which provided, inter alia, that such items could be issued following a request of the Police Authority and made no mention of the Home Secretary’s power to issue the items on his own initiative.R v Secretary of State for the Home Department ex parte Fire Brigades’ Union (1992), the House of Lords ruled that the Home Secretary had no power under the prerogative to amend the Criminal Injuries Compensation Scheme – itself set up under the prerogative – where an Act of Parliament provided for its amendment (even though the relevant provisions had not been brought into force).

In an important case of Council for Civil Service Unions v Minister for the Civil Service (1985), The Prime Minister, acting in her capacity as Minister for the Civil Service, issued an oral instruction under the Civil Service Order in Council 1982 (an order of the Privy Council authorising the use of the prerogative) banning continued membership of trade unions at GCHQ, the government’s communications headquarters – an ‘intelligence’ facility which collects signals intelligence from around the world.The union challenged this exercise of power, claiming that there was a breach of natural justice in the failure of the government to continue negotiations in an industrial relations dispute. The government, having lost in the High Court, pleaded national security in the Court of Appeal and won. The House of Lords upheld the decision of the Court of Appeal, ruling that the courts had no jurisdiction to intervene in matters of national security.It was shown that the courts had the jurisdiction to review (through judicial review proceedings) prerogative acts in the same manner as acts under an Act of Parliament. Also, the House of Lords ruled that while there was equal power to review, the courts would only review prerogative acts that did not involve matters of high policy, which were best left to be determined by the executive.

Since the GCHQ case a number of further issues have been regarded as justiciable. For example, in the case of R v Secretary of State for Foreign and Commonwealth Affairs ex parte Everett (1989), it was held that the prerogative power to issue passports is reviewable.There are two principal means by which Parliament may control exercises of the prerogative. First Parliament may decide to abolish the prerogative and place the relevant powers under statutory authority.

Second, Parliament will call the government to account for its exercise of the prerogative. Parliament may also declare certain former prerogative powers to be unlawful and place them firmly within Parliament’s power.A recent example is the Treasure Act 1996 which abolished the prerogative to treasure trove. However, we shall see below that unless the prerogative is expressly abolished, it will remain as a source of power but one which cannot be exercised while a statute regulating the same subject matter is in force. Theoretically Parliament has ample powers to scrutinize exercises of the prerogative through such procedures as question time, debates and Select Committee enquiries.

In practice, however, the extent of scrutiny is more problematic.By convention there are a number of matters that are immune from parliamentary questions. These include: matters relating to the appointment of ministers, dissolution of Parliament, judicial appointments, government contracts, national security, diplomatic relations, and issues governed by confidentiality. In relation to defence, there are precedents for not answering questions on details of arms sales, operational matters and the giving of military assistance to other states.Advice given by Law Officers of the Crown is also immune from questioning, as is the decision whether or not to prosecute taken by the Director of Public Prosecutions.

The Constitutional Reform and Governance Act 2010 provides for parliamentary scrutiny of treaties and a statutory basis for the civil service. The Parliament Act 2011 also brings the dissolution of Parliament under statutory authority, thereby removing the power of the Crown over the dissolution of Parliament. All reform of the prerogative, however, entails constitutional and legal challenges.It has also been seen in relation to the GCHQ case that the courts have developed a category of non-justiciable matters which protect the judges from encroaching on decision which, in the light of separation of powers, are within the proper sphere of decision of the democratically accountable executive. It is common in all constitution that there will be a number of powers reserved to the executive.

However, it must be controlled because the prerogative power would give rise to the problem of abuse of power and injustice.The prerogative power, in nature, is not consistent with the concept of democracy because it is not enough accountable to the citizen. Under the British constitution, without strict separation of powers, Parliament and the courts have the power to intervene the exercise of the prerogative power by the executive. However, the parliamentary control along with the judicial control over the exercise of prerogative power is not adequate. There is still a reservoir of power is not amenable to either controls.