Introduction
Prerogative powers, historically rooted in the authority of the monarchy, represent a unique aspect of the UK’s unwritten constitution. These powers, now largely exercised by the government, encompass a range of executive functions, including foreign affairs, defence, and the appointment of ministers. However, their scope and susceptibility to judicial review remain contentious in UK law. This essay explores whether prerogative powers are reviewable, examining their nature, the evolving role of judicial oversight, and key case law that has shaped this debate. By analysing the tension between executive authority and the rule of law, the essay will argue that while prerogative powers are increasingly subject to judicial scrutiny, significant limitations persist. This discussion will provide a broad understanding of the legal framework, with a focus on the balance between democratic accountability and executive autonomy.
The Nature and Scope of Prerogative Powers
Prerogative powers are residual powers derived from the Crown, historically exercised by the monarch but now largely delegated to ministers in the modern constitutional framework. As defined by Dicey, these powers are “the residue of discretionary or arbitrary authority… legally left in the hands of the Crown” (Dicey, 1885). They include critical functions such as declaring war, entering treaties, and granting pardons. Unlike statutory powers, prerogative powers are not derived from legislation, which raises questions about their accountability and oversight.
Importantly, the lack of a codified constitution in the UK means that the boundaries of these powers are often determined by convention and judicial interpretation rather than explicit legal text. This ambiguity can lead to conflicts between the executive’s desire for autonomy and the judiciary’s role in upholding the rule of law. Indeed, while prerogative powers are essential for efficient governance, their potential for abuse necessitates some form of oversight. The question remains whether the courts, as guardians of legality, have the authority to review such inherently executive functions.
Judicial Review of Prerogative Powers: Historical Perspective
Historically, the judiciary adopted a hands-off approach to prerogative powers, viewing them as matters of political discretion beyond judicial reach. This deference is evident in early cases such as the Case of Proclamations (1611), where it was established that the Crown could not create new prerogatives or alter the law without parliamentary consent. However, the courts refrained from scrutinising the exercise of existing prerogatives, considering them a matter for the executive alone.
This position began to shift in the 20th century as the principle of the rule of law gained prominence. The landmark case of Council of Civil Service Unions v Minister for the Civil Service (1985), commonly known as the GCHQ case, marked a significant turning point. Here, the House of Lords held that the exercise of prerogative powers could be subject to judicial review on grounds of illegality, irrationality, and procedural impropriety (Lord Diplock, 1985). This decision expanded the judiciary’s role, affirming that executive actions, even under prerogative powers, must comply with legal principles. However, the court also noted exceptions, suggesting that certain “high policy” areas, such as national security, might remain non-justiciable, reflecting a lingering judicial reluctance to fully encroach on executive territory.
Contemporary Developments and Limitations
The reviewability of prerogative powers has been further tested in recent decades, particularly in high-profile cases involving constitutional crises. A notable example is R (Miller) v Secretary of State for Exiting the European Union (2017), often referred to as the first Miller case. The Supreme Court ruled that the government could not trigger Article 50 to begin Brexit negotiations using prerogative powers without parliamentary authorisation. The court reasoned that such an action would fundamentally alter domestic law, which falls outside the scope of prerogative authority (Supreme Court, 2017). This decision underscored the principle that prerogative powers cannot override statutory rights or parliamentary sovereignty, reinforcing the judiciary’s role in limiting executive overreach.
More recently, R (Miller) v The Prime Minister (2019), or Miller II, addressed the prorogation of Parliament by Prime Minister Boris Johnson. The Supreme Court unanimously held that the decision to prorogue was unlawful because it frustrated Parliament’s ability to carry out its constitutional functions without reasonable justification (Supreme Court, 2019). This case further demonstrated the judiciary’s willingness to scrutinise prerogative powers when they interfere with democratic processes. However, it also highlighted the judiciary’s careful framing of its role, focusing on legality rather than the political merits of the decision, thus maintaining a degree of deference.
Despite these developments, limitations to judicial review persist. Areas such as national security and foreign affairs often remain outside judicial scrutiny due to their political sensitivity. For instance, in R v Jones (Margaret) (2006), the courts declined to determine the legality of the Iraq War, citing that such matters are inherently non-justiciable. This reflects an ongoing tension: while the judiciary has expanded its oversight, it remains cautious about overstepping into realms traditionally reserved for political judgement. Arguably, this balance is necessary to preserve the separation of powers, though it raises questions about accountability in critical areas of governance.
Critical Analysis: Balancing Executive Power and Rule of Law
The evolving judicial approach to prerogative powers reveals a broader struggle to balance executive efficiency with the rule of law. On one hand, the expansion of judicial review, as seen in GCHQ, Miller I, and Miller II, demonstrates a commitment to ensuring that executive actions are lawful and accountable. These decisions reflect a growing recognition that unchecked prerogative powers could undermine democratic principles, particularly in a system lacking a written constitution to delineate clear boundaries.
On the other hand, the judiciary’s reluctance to intervene in certain areas suggests a pragmatic awareness of its limitations. Courts are ill-equipped to assess matters of high policy, where expertise and political judgement are paramount. Furthermore, excessive judicial intervention risks blurring the separation of powers, potentially undermining the executive’s ability to govern effectively. This delicate balance is central to the debate on reviewability, as it underscores the challenge of ensuring accountability without paralysing government action.
Conclusion
In conclusion, prerogative powers in UK law are increasingly reviewable, as evidenced by landmark cases like GCHQ, Miller I, and Miller II, which have expanded judicial oversight over executive actions. These developments reflect a broader commitment to the rule of law and parliamentary sovereignty, ensuring that prerogative powers cannot be exercised in ways that undermine democratic principles. However, significant limitations remain, particularly in areas of high policy such as national security and foreign affairs, where judicial deference persists. This balance between reviewability and non-justiciability highlights the complexities of the UK’s constitutional framework, where the absence of a codified constitution necessitates judicial caution. Ultimately, while the judiciary plays a vital role in checking executive overreach, the reviewability of prerogative powers remains partial, leaving room for further debate on how best to ensure accountability without compromising governance. The ongoing tension between these competing principles will likely continue to shape the legal and political landscape in the years ahead.
References
- Dicey, A.V. (1885) Introduction to the Study of the Law of the Constitution. Macmillan.
- Lord Diplock (1985) Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374. House of Lords.
- Supreme Court (2017) R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5. Supreme Court of the United Kingdom.
- Supreme Court (2019) R (Miller) v The Prime Minister [2019] UKSC 41. Supreme Court of the United Kingdom.
- R v Jones (Margaret) [2006] UKHL 16. House of Lords.
