Introduction
The separation of powers is a doctrine concerned with the division of governmental authority to prevent the concentration of power and the potential for tyranny. This principle, often cited in constitutional theory, promotes a system where the legislative, executive, and judicial functions are, to some degree, allocated to distinct bodies. The doctrine is intended to produce a balanced system of checks and controls, with each branch having defined, though sometimes overlapping, areas of responsibility. The requirements of the separation of powers, within any given constitution, are fundamentally rooted in the need to safeguard individual liberties and uphold democratic principles. The doctrine, rather than being a strict descriptive principle, must be understood as a functional concept aimed at preventing the abuse of power and promoting efficiency.
Defining the Separation of Powers: Rejecting a Purely Descriptive Model
The concept of the separation of powers, in its purest form, suggests a tripartite division of governmental authority, with each branch functioning independently and exclusively within its defined sphere. However, the complexities of modern governance often blur these lines. Administrative authorities, for example, may exercise functions that combine legislative, executive, and judicial elements, thus challenging a strict, descriptive understanding of the separation of powers. To adhere to the notion of a fully separate system would mean disregarding the practical ways in which government functions. Rather, a more adaptable, functional view of the doctrine is required. This perspective originates from the writings of Aristotle in Politics, where he identified a threefold classification of power. This was further developed by Montesquieu's L'Esprit des Lois, wherein he emphasized the risks of concentrating judicial, legislative, and executive powers within a single entity, thereby leading to oppression. Therefore, the fundamental function of the separation of powers, at its most basic level, is to separate power for an "advantageous" purpose, rather than a mere description of three branches. The core purpose, as conceived by Montesquieu, is the protection of the population from tyranny and oppression, as also supported by constitutional writers like Barendt who notes the separation as "only a means to achieve that end." Barber emphasizes the promotion of efficiency as a core function, indicating that varied interpretations of the doctrine's aims are immaterial to its validity so long as a form of separation exists to achieve a functional purpose.
Reconciling Parliamentary Sovereignty with Judicial Separation
A significant argument against the applicability of the separation of powers in the United Kingdom is the assertion that it is incompatible with the principle of parliamentary sovereignty. Parliamentary sovereignty maintains that the legislature holds ultimate legal authority. However, an understanding of separation of powers, not as an equal distribution of power but rather a functional division of roles, allows reconciliation with this doctrine. In this respect, parliamentary sovereignty results in a two-factor separation. Parliament formulates the law, and the judiciary interprets it. This judicial role extends to protecting parliamentary intent from executive overreach, thus supporting parliamentary sovereignty itself. Lord Diplock, in Duport, stated the constitution "is firmly based upon the separation of powers: Parliament makes the laws, the judiciary interpret them". This indicates an independent function of the judiciary that goes beyond a mere interpretive capacity. The independence of the judiciary is important to preventing arbitrary executive power, as suggested by Lord Steyn. The Constitutional Reform Act 2005 further emphasizes judicial separation by establishing the Supreme Court as a distinct entity outside of Parliament, separating the judicial function of the Lord Chancellor from its other governmental roles. This formalization acts as a “constitutional guarantee” as described in the government’s consultation paper A Supreme Court for the United Kingdom. Moreover, the location of the Supreme Court hearings, now in the Middlesex Guildhall, as opposed to within Parliament, establishes a physical separation. Furthermore, the judicial review of prerogative power, evident in cases like De Keyser, demonstrates the courts' role in ensuring executive compliance with the laws of the land and therefore protecting Parliament’s legislative intent, where statutory provisions take primacy over the prerogative. This is further affirmed by Lord Steyn in Anderson, who highlights the principle of the courts' exclusive role of judicial functions as essential for maintaining governmental separation, in view of compliance with the European Convention on Human Rights (ECHR).
Efficient Separation: A Westminster Model Perspective
Another point of contention against the separation of powers in the UK system arises from the Westminster model, which is characterized by a fusion of the executive and legislative branches. However, this fusion can be seen as a mechanism promoting efficiency rather than being an incompatibility with the doctrine itself. Barber argues that the separation of powers, in addition to its tyranny-preventing function, also promotes efficiency by creating a division of labor and establishing institutions. The legislature, with its varied opinions, debates and rejects proposals on the basis of democratic authority, and the executive, with its expertise, can contribute effectively to the drafting of the legislation. In a process that requires consensus and efficiency, the partial fusion of these branches can promote this. Such separation is subtle, rather than absolute, as shown in s2 of the House of Commons Disqualification Act, where limiting the number of ministers in Parliament allows the legislative chamber to better carry out its debating and rejecting functions. The judiciary also participates in the efficient separation of powers. Given their legal expertise, courts are well-suited to resolving discrete disputes according to law. The 17th-century case, Prohibitions, demonstrates this, where a resolution of legal disputes by the Monarch was seen as improper given the “long study and experience” necessary to apply the law. The case was not based on tyranny prevention, but on efficiency grounds, supporting Barber’s view of an efficiency-promoting function of the doctrine.
The Human Rights Act and the Separation of Powers
The Human Rights Act 1998 (HRA) has had a significant impact on the separation of powers in the UK. It has placed an obligation on public authorities, including the courts, to act in a manner compatible with the European Convention on Human Rights (ECHR). While preserving parliamentary sovereignty, the HRA requires the courts to interpret legislation, where possible, in compliance with ECHR rights. In instances where this interpretation is impossible, the courts can issue a declaration of incompatibility. This creates a political, but not legal, obligation to address the identified incompatibility. This mechanism, known as ‘remedial power’, has successfully led to changes in legislation such as the Asylum and Immigration (Treatment of Claimants, etc.) Act 2004 and the Sexual Offences Act 2003. This illustrates a nuanced separation of powers where courts scrutinize laws for human rights violations while Parliament retains the authority to create and amend legislation. The judiciary's role in protecting human rights under the HRA reinforces the functional purpose of the separation of powers, by preventing abuse of power. The adoption of the principle of proportionality following the enactment of the HRA, allows courts to place a burden on decision-makers to justify limitations on human rights, as seen in R (on the application of Daly) v Secretary of State for the Home Department. This standard, which places the burden on the decision-maker, differs from the concept of irrationality as established in Associated Provincial Picture Houses Ltd v Wednesbury Corp and, allows for a more intense judicial review. The difference between these principles is shown by comparing Smith and Grady v United Kingdom with R (on the application of Daly) v Secretary of State for the Home Department.
Judicial Review and the Functional Separation of Powers
Judicial review is a mechanism through which the judiciary supervises the executive's exercise of discretionary powers given by Parliament. It is designed to safeguard parliament as the supreme law-maker, but also ensures the executive acts within the boundaries of the law. The court’s role in judicial review is to examine decisions for legality, rationality and procedural propriety, rather than the merits of the decision itself. This acts to ensure a balance between branches and to ensure that judicial power is not abused. In addition to the traditional grounds of review, the courts also consider legitimate expectations of individuals that have been created by a public body through a process or promise. This body of law, called ‘natural justice’, helps ensure fairness in public decision-making. The courts also ensure public bodies act without bias, where fairness is not only maintained but seen to be maintained, according to R v Sussex Justices, Ex parte McCarthy. Additionally, judicial review serves to promote transparency and uphold the rule of law, holding public bodies to account and safeguarding against arbitrary decisions.
Conclusion
The claim that the separation of powers is not a feature of the UK constitution is invalidated by the fact it is based on a pedantic definition of the doctrine, which overlooks its heart: the prevention of tyranny and the promotion of efficient government. While it is true that the UK constitution does not adhere to a rigid, descriptive model of the separation of powers, a functional understanding of the doctrine reveals a system of checks and balances that exists to protect individual liberties and democratic principles. The judicial role in protecting Parliament’s intent, as well as human rights and the limits of executive power, showcases the practical operation of the separation of powers. The fusion of the executive and legislative branches, often cited as an example against the separation of powers, can also be understood as a means to enhance legislative efficiency. The courts have used their inherent powers to create legal principles which support and work with Parliament, as seen in Pickin v British Railways Board. The judicial review of executive actions supports the concept of checks and balances. As Bogdanor states, "The old constitution was based upon the sovereignty of Parliament, the new constitution is based on the idea of a constitutional state based upon a separation of powers." This indicates a shift towards a model that recognizes the functional separation of powers as an essential element of the UK's constitutional framework.
