Introduction
The royal prerogative is a unique source of government power in the UK constitution. Described by A.V. Dicey as the "residue of discretionary or arbitrary authority, which at any given time is legally left in the hands of the Crown" (Dicey, 1959), these powers derive from the common law and are exercised by government ministers on behalf of the Monarch. For much of history, the courts maintained a deferential, 'hands-off' approach to the prerogative. However, the last few decades have seen a significant shift, prompting debate about the proper role of the judiciary in scrutinising executive action. This essay will examine the evolution of the courts' approach to the royal prerogative. It will argue that, despite a landmark ruling in the 1980s that opened the door to review, the courts have remained largely cautious. Therefore, while recent high-profile cases have led to accusations of overreach, the more persistent criticism that the judiciary has shown too little activism in this area is more persuasive.
The Traditional Approach: A Limited Judicial Role
Historically, the courts’ role in relation to the prerogative was extremely limited. The judiciary accepted that it had the power to determine the existence and scope of a prerogative power, but it would not question the manner in which that power was exercised. This principle was established centuries ago. In the Case of Proclamations (1611), the court held that the King could not create new offences or change the common law by proclamation, thus defining the limits of the power. Similarly, in Attorney-General v De Keyser’s Royal Hotel Ltd (1920), the House of Lords confirmed that the prerogative could not be used to take property when a statute already governed the matter.
These cases show the courts policing the boundaries of the prerogative. If government ministers acted under a prerogative power that did not exist, or which had been superseded by statute, the courts would intervene. However, for well-established prerogative powers, such as the conduct of foreign affairs, the deployment of armed forces, or the granting of honours, the exercise of that power was considered non-justiciable. This meant it was beyond the scope of judicial review. The rationale was rooted in the separation of powers; such decisions were deemed to be political in nature and therefore matters for the executive and Parliament, not for unelected judges. This created 'no-go' areas for the courts, leaving significant government powers without judicial oversight.
The Turning Point: The GCHQ Case
The traditional position was dramatically altered by the House of Lords' decision in Council of Civil Service Unions v Minister for the Civil Service (1985), commonly known as the GCHQ case. The case concerned a decision made by the Prime Minister, using the prerogative, to ban trade union membership at the Government Communications Headquarters. The unions sought judicial review, arguing that they had a legitimate expectation of being consulted before such a change was made.
The House of Lords established a new and crucial principle. Lord Diplock stated that the key question was not the source of a power (i.e., statute or prerogative) but its subject matter. He famously argued that he could see "no reason why" a decision made under the prerogative should "be immune from judicial review… merely because the decision is one which affects the private rights or legitimate expectations of an individual" (GCHQ, at 410). This landmark ruling swept away the old rule that the exercise of prerogative power was automatically immune from review.
However, the ruling was not a complete victory for judicial activism. Lord Diplock and other Law Lords, such as Lord Roskill, identified a number of prerogative powers that would likely remain non-justiciable because their subject matter made them unsuitable for judicial review. These 'excluded categories' included decisions relating to national security (which was the reason the unions ultimately lost their case), the making of treaties, the defence of the realm, the prerogative of mercy, and the dissolution of Parliament. The courts, therefore, opened the door to review but immediately signalled that they would not enter certain rooms.
Post-GCHQ: An Era of Judicial Caution
The argument that the courts have shown too little activism is supported by their approach in the years following GCHQ. While the case established the principle of reviewability, in practice, judges have often been reluctant to intervene, particularly in the 'excluded categories' of high policy. The judiciary has shown considerable deference to the executive in these sensitive areas.
A clear example is R (Abbasi) v Secretary of State for Foreign and Commonwealth Affairs (2002). This case involved a British citizen detained at Guantanamo Bay. His family sought an order compelling the Foreign Office to make representations to the US government on his behalf. The Court of Appeal acknowledged that the claimant had a legitimate expectation that the government would at least consider his request. However, it refused to order the Foreign Office to do anything specific, stating that foreign policy was a matter for the executive. The court would recognise the existence of the government's duty, but it would not police its performance. This demonstrates a deep-seated reluctance to become entangled in the conduct of diplomacy.
Similarly, in R (Bancoult) v Secretary of State for Foreign and Commonwealth Affairs (No 2) (2008), the House of Lords considered the government's use of prerogative Orders in Council to prevent the Chagos Islanders from returning to their homeland. A majority found that the government's action was lawful, giving significant weight to the executive's assessment of foreign policy and defence needs. This decision was seen by many critics as overly deferential and a retreat from the promise of meaningful review held out by GCHQ. These cases illustrate that even when fundamental rights are at stake, the courts often step back when faced with matters of high policy, supporting the view that judicial review of the prerogative has been too limited.
The Miller Cases: Too Much Activism at Last?
The narrative of judicial caution has been complicated by two recent and highly significant Supreme Court rulings. These cases, known as Miller No. 1 and Miller No. 2, led to accusations that the courts had finally gone too far and engaged in excessive judicial activism.
In R (Miller) v Secretary of State for Exiting the European Union (2017) (Miller No. 1), the Supreme Court ruled that the government could not use the prerogative power to conduct foreign affairs to trigger Article 50 of the Treaty on European Union. The court held that doing so would frustrate the purpose of the European Communities Act 1972 and remove rights granted by Parliament. The ruling reaffirmed the long-standing principle of parliamentary sovereignty: the prerogative cannot be used to override statute.
More controversially, in R (Miller) v The Prime Minister (2019) (Miller No. 2), the Supreme Court held that the Prime Minister's advice to the Queen to prorogue Parliament for five weeks was unlawful. The court reasoned that the prorogation had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions without reasonable justification. The decision was groundbreaking because it saw the court stepping into the exercise of a core prerogative power that many had assumed was non-justiciable. Critics argued this was a political decision that trespassed on the executive's domain. However, the Supreme Court framed its judgment not as a review of the exercise of the power, but as a determination of its legal limits. It held that a prerogative power to prorogue Parliament cannot be unlimited if it is to be compatible with the fundamental constitutional principle of parliamentary sovereignty. In this way, the court connected its decision back to the traditional judicial role of policing the boundaries of prerogative power, even as it dramatically expanded what that role entailed.
Conclusion
The courts' approach to the royal prerogative has clearly evolved from one of near-total deference to a more interventionist stance. The GCHQ case was the critical moment that established the principle that the exercise of prerogative power is not automatically immune from judicial review. However, the subsequent case law demonstrates that this change did not lead to a wave of aggressive judicial activism. In many areas, especially those touching on foreign policy, defence, and national security, the courts have remained highly cautious, leading to the valid criticism that they have done too little to hold the executive to account.
The Miller cases represent a significant development, showing the Supreme Court's willingness to intervene to protect fundamental constitutional principles. Yet even these bold decisions were carefully justified by reference to the traditional judicial function of defining the legal limits of power. Therefore, it is an oversimplification to see the courts' approach as being simply 'too little' or 'too much' activism. A more accurate picture is one of a judiciary engaged in a difficult balancing act. It has expanded its oversight but remains aware of its own constitutional limits, intervening decisively only when it perceives a fundamental threat to the rule of law or parliamentary sovereignty. On balance, the historical and ongoing evidence of judicial deference in many key areas suggests that the main drawback has indeed been an excess of caution, not an excess of activism.
References
- Attorney-General v De Keyser’s Royal Hotel Ltd [1920] AC 508.
- Case of Proclamations (1611) 12 Co Rep 74.
- Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374.
- Dicey, A.V. (1959) An Introduction to the Study of the Law of the Constitution. 10th ed. Macmillan.
- R (Abbasi) v Secretary of State for Foreign and Commonwealth Affairs [2002] EWCA Civ 1598.
- R (Bancoult) v Secretary of State for Foreign and Commonwealth Affairs (No 2) [2008] UKHL 61.
- R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5.
- R (Miller) v The Prime Minister [2019] UKSC 41.
