The orthodox tripartite division of legislature, executive, and judicial powers can be found to have originated in the 18th century within the works of Montesquieu titled as ‘De l’Esprit des Lois’ (1748). The doctrine in its pure institutional form holds that each governmental function should be vested exclusively in a separate and independent body. In conventional terms, the legislature enacts general rules, the executive seeks to implement them, and the judiciary applies them in resolution of the disputes. The following model had emerged in post-revolutionary France and the US Constitution of 1787, where both instruments had adopted a structural separation to safeguard against any concentration of power within a single branch. Contrastingly, the British Constitution had evolved incrementally without any revolutionary breakthrough, which is reflective of a different historical trajectory that had been adopted by the United Kingdom that had complicated the application of this strict separation model.
The essay agrees with the statement in question that there exists a fusion of powers, functions, and personnel in UK’s Westminster Model of uncodified constitution. It is also of a great strength. It enables smooth functioning of government, delivery of services, protection of fundamental rights, and resolution of deadlocks without formal legal procedures, such as constitutional amendments. At the same time, the fusion has enabled an executive controlled House of Commons and capture of legislative functions by powerful executive led often by majoritarian politics and populist leaders. This represents a threat to UK’s constitution for which greater separation through codification of constitution (wholly or party) may be required, while retaining the flexible model of separation.
This tripartite scheme assigns discrete categories of different governmental functions where the legislative function entails the making of legally binding or applicable rules, the executive function entails the conduct of foreign relations, defence, administration, and policy development across various areas, the judicial function entails the impartial application of law for the purposes of adjudicating the disputes and trying criminal or civil cases. In personal terms, this doctrine holds that no single individual may simultaneously hold office in more than one branch. On these lines, a judge should not serve as a minister or a member of the parliament. This may appear to be theoretically neat; however, the personal separation rarely occurs in absolute form as even in rigid presidential systems such as that of the United States of America, it can be seen that there are certain practical overlaps and interdependencies within their roles.
The parliamentary system of the United Kingdom can be found to openly depart from this personal separation ideal that had been propounded by these theorists. Ministers exercise a dominant role in lawmaking because they constitute as the executive and are drawn from the members of the legislature. The role of executive is sharply integrated within the parliament and it stands in clear contrast to other systems which prevail in the United States or Brazil where the executive and the legislature are deemed to be institutionally distinct and are elected separately. The United Kingdom model signifies how constitutional systems inherently may be able to reject this rigid separation of power for the purposes of political fusion. This raises doubts about whether the thesis of Montesquieu in strict tripartite framework is actually reflective of the modern forms of governance in jurisdictions such as the United Kingdom.
Contemporary scholarship had often deemed the doctrine of separation of powers to demand rigid institutional exclusivity. The main aim is the prevention of any excessive power to be concentrated in one organ, for instance, when the parliament delegates the legislative authority to the ministers by way of secondary legislation, then the judicial review acts as a counterweight which ensures that the executive role in rule making is compliant to the statutory limits. This interdependence determines that separation is not an end in itself, but it is a part of the balance which is designed to uphold the accountability of these organs of the State.
Extensive debates within the academic circles emerged over the doctrine of separation of powers in the United Kingdom within the political and legal constitutionalist school of thoughts. Political constitutionalists such as Adam Tomkins argue that the United Kingdom's parliamentary system is primarily controlled by political mechanisms as opposed to the courts. Tomkins contends that ministerial responsibility; parliamentary scrutiny ; and electoral accountability form the core architecture for the mechanism of conducting checks and balances upon executives' powers. In this context, the judicial intervention should be interpreted to operate only in exceptional circumstances. This view finds consonance with the doctrine of parliamentary supremacy as upheld by AV Dicey, who held that Parliament remained legally omnipotent and politically answerable to the electorate only. In the case of R( Anderson) vs Secretary of State for Home Department, Lord Bingham had been found to have acknowledged the constitutional role of the Parliament and the executive lays in criminal justice policy but yet at the same time, the House of Lords noted that it was necessary to curtail executive sentencing powers which was illustrative of the tension between these political and legal controls. In the Belmarsh case, the House of Lords had found that the infinite detention powers pursuant to the Anti-Terrorism, Crime and Security Act 2001 was incompatible with the ECHR as Lord Hoffman had raised the imperative that the ultimate responsibility to uphold national security would lay with the Parliament in pursuance of the political constitutionalist line of reasoning.
On the other hand, the legal constitutionalists seek to emphasise that the role of the judiciary amounts as an equal branch which is responsible to uphold the fundamental rights of the individuals while upholding accountability and legality in their functioning. Legal constitutionalists argue that political processes by themselves cannot guarantee accountability, especially in those times where the parliament is formed by a strong majority government and that majority discipline dilutes the overall parliamentary scrutiny. In such circumstances, judicial review may amount as a constitutional necessity, as reflected in the House of Lords decision in Jackson vs Attorney General. In this case, Lord Steyn and Baroness Hale had suggested that parliamentary supremacy is subject to judicial limits in certain cases which positioned the courts to amount as a guardian of constitutional fundamentals. In R(Evans) vs Attorney General, the Supreme Court held that the right to publish the letters of Prince of Wales and had overruled the ministerial veto. This decision demonstrated that judicial authority had amounted to safeguard the individuals against executive attempts to evade any transparency obligations. In R( Miller) vs Prime Minister, the United Kingdom Supreme Court had invalidated the prohibition of the parliament and had justified its decision to amount as a defence for parliamentary democracy which allowed the court to resort to separation principles so that legislative oversight could be upheld.
Both perspectives described above acknowledge that the UK's unwritten constitution renders the strict separation model to be impossible. The interdependence of the political and legal checks seeks to ensure that the functional separation is aimed to curb power concentration. It appears that when the parliament delegates their legislative authority to ministers by way of secondary legislation, then the courts are in a position to adopt judicial review to ensure that these powers are exercised within their limits. These debates shape the interpretations adopted towards the UK political structure in terms of fusion of powers that undermine separation. Political constitutionalists argue that the judiciary amounts as a subordinate actor within the parliamentary system, whereas legal constitutionalists hold that it amounts as an indispensable check, where this tension is further aggravated in the periods of executive dominance where political checks may not be as straightforward. This analysis reveals that the United Kingdom constitution resists the classification as purported by Montesquieu under the tripartite model. It must be noted that this rhetoric of separation of powers remains powerful, however, its role in the balance of institutional powers amounts as its primary justification as opposed to the imperative of maintaining rigid exclusivity. This raises questions whether the prevalence of the doctrine of separation of powers is justified on the account of its structural purity or in the tendency to adopt to the realities of United Kingdom's governance. The evolving jurisprudence of the courts suggests that separation of powers in the United Kingdom should be best understood as a dynamic equilibrium between legal safeguards and political processes.
One of the complexities which arise in the context of the UK unwritten constitution is its evolving institutional architecture that had followed the constitutional reforms in the late 20th and early 21st century. One of such reforms was the Constitutional Reform Act 2005, which had significantly configured the relationship between the judiciary and other branches of the state. The 2005 Act had further established the United Kingdom Supreme Court and transferred all the judicial functions of the House of Lords to this independent judicial body. This move can be appreciated as a step forward towards a clearer demarcation between judicial authority and the legislative role nevertheless, this reform did not completely sever the underlying functional overlaps, as judges still play a central role in terms of interpreting and applying statutes, which had been shaped up by the ministers and the executives who are legislators as well. This illustrates that the institutional separation is tempered by interpretive interdependence that cannot be severed without drastically altering the constitutional landscape of the United Kingdom.
The introduction of the Judicial Appointment Commission under the CRA 2005 had marked a structural adjustment to the constitutional landscape which had aimed to counter the long-standing concerns in relation to the influence of the Executive over the appointments of the Judiciary. Before its establishment, appointments to the Senior Judiciary were largely a matter of the Lord Chancellor, who might simultaneously hold an office in the Cabinet. He would preside over the House of Lords and amount as the head of the Judiciary. This arrangement had been widely criticized by academics as it contravened the appearance of the judicial independence. According to Masterman, the creation of this commission was both a symbolic and a functional step in terms of securing an institutional distance amongst the members and the process of judicial selection. The new process had further mandated that appointments are to be made on merit, which followed an open and transparent selection procedure, as the role of the Lord Chancellor had been reduced to limit capacity in terms of only accepting, rejecting, or requiring reconsideration of the purported recommendations. This can be described as an institutional insulation which is not absolute in nature. Weber and Gee argued that judicial independence is still framed within the constitutional settlement where Parliament would remain supreme and the appointment process would ultimately be deemed as a statutory creation of the Parliament.
The Judicial Accounts Commission is accountable to the Parliament, whereas the legislature is required to compose, remit, and devise procedures that are subject to further amendments. This reflects that while the reform may mitigate the risk of direct executive patronage, however, the judiciary's personal framework would still be embedded deeply within the legal and the political architecture that had been designed and controlled upon by the Parliament. In these terms, it appears that the separation of powers in the United Kingdom bears the tendency towards functional interdependence as opposed to pure autonomy.
Another illustration of a qualified autonomy can be found in the operation of the devolved legislature found in Scotland, Wales, and Northern Ireland. Each devolution settlement had been conducted through various statutory acts such as Scotland Act 1998, Government of Wales Act 2006, and Northern Ireland Act 1998, which have found to have conferred primary legislative and executive authority over certain matters. The perusal of these powers reveals that these are constitutionally delimited and suffer disputes over their operation, which is adjudicated through the United Kingdom Supreme Court. Examples of such disputes can be found within the application of s29-33 of the Scotland Act 1998, which exemplifies what Mollers described as a vertical separation of powers, as the legislative authority is found to have dispersed through different tiers of government where the judicial authority is upheld as the arbiter of competence.
In practical terms, the resolution of these devolution conflicts usually occur through political negotiation as opposed to immediate litigation. For instance, the intergovernmental mechanisms found under the Memorandum of Understanding and Joint Ministerial Committee seeks to allow the disputes to be addressed outside the courts. And when the political resolution fails, as illustrated in Imperial Tobacco vs. Lord Advocate, the judiciary is then called upon for the purposes to enforce the statutory limits on the devolved competence. This appears to be a duality where the judicial oversight coexists with political bargaining that is demonstrative of the constitutionalism adopted by the United Kingdom in terms of blending the mechanism which encourage cooperative governance within the imperative of separation of powers.
The Human Rights Act 1998 also had found to reshape interaction between the branches of the state where the judiciary had been empowered to issue declarations of incompatibility where primary legislation would find to have conflicted with the European Convention of Human Rights. It must be noted that this mechanism does not outrightly permit the courts to strike down the actions of the Parliament but it creates a structural dialogue between legislature and the judiciary which may be contributed towards the obscurity of functional divisions between these two institutions. It appears to be a dialogue-based model which is reflected of the incremental constitutionalism observed within the United Kingdom where separation of powers amounts as a normative framework that guides the relationships between the institutions as opposed to a rigid legal blueprint.
The developments in the judicial review had further expanded the tendency of the judiciary to hold a supervisory role over executive decision-making beyond the ultra vires grounds which were upheld conventionally in those cases where proportionality and legitimate expectation claims are contested. Such an extension may arguably strengthen the legal constitutionalist approach that courts may act as a necessary counter in periods of strong executive dominance yet at the same times it may be adverse to the doctrine of parliamentary supremacy that ensures that judicial assertiveness may operate within accepted political boundaries to avoid judicial dictatorship which is observed in constituted in jurisdictions bearing rigid constitutions such as that of the United States of America.
In conclusion, having analysed the statutory principles, common law, international instruments and academic criticisms, the normative position appears to be that these developments show UK’s constitutional framework derives its resilience from fusion and compartmentalization of powers coupled with institutional flexibility. This resilience can be attributed to the institutional flexibility which is capable to accommodate both independence and interdependence of these institutions. The Judicial Appointment Commission is representative of a deliberate effort for the purposes to insulate the judiciary while it retains democratic accountability by way of parliamentary control, whereas devolution reflects the willingness to disperse legislative and executive power while retaining central judicial oversight. In these terms, academics such as Paul Craig argued that separation of powers in the UK must be understood as a dynamic balance which had been shaped by political cultures and its evolution as opposed to its strict adherence to a rigid doctrinal model.
Bibliography
Books
1. Charles de Secondat, Baron de Montesquieu, The Spirit of Laws (The Lawbook Exchange 2005)
2. Roger Masterman, The Separation of Powers in the Contemporary Constitution: Judicial Competence and Independence in the United Kingdom (Cambridge University Press 2010)
3. Christoph Möllers, The Three Branches: A Comparative Model of Separation of Powers (Oxford University Press 2013)
4. Ed Carolan, The New Separation of Powers: A Theory for the Modern State (Oxford University Press 2009)
Book chapters
5. Andrew Le Sueur, Maurice Sunkin and Jo Eric Khushal Murkens, ‘Separating and Balancing Powers’ in Public Law: Text, Cases, and Materials (5th edn, Oxford University Press 2023)
Journal articles
6. Venkatesh Iyer, ‘Separation of Powers: The UK Experience’ (2018) 5 Journal of International and Comparative Law 507
7. Adam Tomkins, ‘The Role of the Courts in the Political Constitution’ (2010) 60(1) University of Toronto Law Journal 1
8. Paul Sales, ‘The Separation of Powers’ (2021) 66(1) American Journal of Jurisprudence 97
9. Eric Barendt, ‘Separation of Powers and Constitutional Government’ in The Rule of Law and the Separation of Powers (Routledge 2017)
10. AV Dicey, ‘The Nature of Parliamentary Sovereignty’ in Introduction to the Study of the Law of the Constitution (Palgrave Macmillan 1979)
Cases
11. R (Anderson) v Secretary of State for the Home Department [2003] 1 AC 837
12. A v Secretary of State for the Home Department [2004] UKHL 56
13. Jackson v Attorney General [2006] 1 AC 262
14. R (Evans) v Attorney General [2015] UKSC 21
15. R (Miller) v the Prime Minister [2019] UKSC 41