The rule of law and the separation of powers have a particularly important role to play within the UK’s unwritten constitution. They allocate and restrain power so as to ensure that the constitutional system remains accountable and limited.

It is a common observation that the UK does not have a written constitution. However, it is the existence of mechanisms such as respect for the rule of law and the operation of a (more or less) rigorous separation of powers together with devices such as constitutional conventions that allows this jurisdiction to lay claim to the existence of a constitution albeit one which is not formally recorded in a written document.

Bradley and Ewing[1] analyse the rule of law by focussing upon three aspects of its operation in contemporary society: the simple maintenance of law and order; the requirement that government be conducted according to the law; the broader concept of the rule of law as a broad political doctrine which goes beyond an analysis of the operation of particular laws and encompasses the values of a free and democratic society. The “law and order” model which holds that order is better than anarchy. The difficulty with this approach is that it is possible thereunder to characterise a military dictatorship as functioning according to the rule of law since a form of order is maintained and courts may even continue to function to resolve private disputes between citizens. However, the authors make the point[2] that “…constitutionalism and the rule of law will not thrive unless legal restraints apply to the government.”

A better approach is to examine the manner in which the courts have the ability to challenge the acts of the Executive and other public authorities. The use of judicial review to scrutinise the actions of Ministers and Government Departments is familiar. Further, in M v Home Office[3] it was even held that a Minister of the Crown could be guilty of contempt of (one of Her Majesty’s) Courts. The argument that the courts had no such powers against ministers met with a stinging rebuttal:

“[This argument] would, if upheld, establish the proposition that the executive obey the law as a matter of grace and not as a matter of necessity, a proposition which would reverse the result of the Civil War.”(!)

The principle has been further reinforced by the adoption of the European Convention on Human Rights which now provides a mechanism by which the very laws of this jurisdiction can be examined to ascertain their “lawfulness”.

The concept of the rule of law as a broad political doctrine has generated much debate. One the one hand, it is possible to argue that the law comprises a set of absolute values distilled from centuries of legal experience; on the other it may be argued that the rule of law is a flexible concept which has to be adjusted in accordance with the prevailing social and political circumstances of the time. Professor Joseph Raz[4] argues that the rule of law is a “political ideal which a legal system may possess to a greater or lesser degree” and that it is “just one of the virtues that a legal system may possess and by which it is to be judged”. Raz therefore does not invest the rule of law with any inherent moral authority stating expressly that it “is not to be confused with democracy, justice, equality (before the law or otherwise) human rights of any kind…” While this approach may be highly respected from a jurisprudential perspective, it is of little value in understanding the operation of the rule of law in the UK constitution. A far more preferable and workmanlike analysis is that of Friedrich von Hayek in the seminal work The Road to Serfdom[5]. He propounds the thesis that the function of the rule of law is to ensure that the government is bound in all its actions by rules fixed and announced beforehand. Such a state of affairs makes it possible to predict how the government will employ its coercive powers in a given situation and to plan one’s individual affairs on this basis. Thus the rule of law in the UK constitution is founded upon certainty: laws are democratically debated and publicly promulgated and, as a general rule, do not operate retrospectively. The UK citizen is therefore protected from the “whim of the tyrant” approach to lawmaking and has the added shield of the power of the courts (domestic and European) to review government action and the validity of the laws themselves.

In order for such a system to be maintained, especially in the absence of a written constitution to which recourse may be had in the event of alleged injustice (as in the USA), it is essential that there be a clear separation of powers between the three branches of government: Executive, Legislature and Judiciary. This separation is clear cut in the USA – the President forms the Executive, Congress is the Legislature and the same personnel cannot serve in both (save that the Vice-President chairs the Senate). Government action can be reviewed by the Supreme Court. In the UK, as might be expected given the historical evolution of the constitution as opposed to its imposition by a written document, there are certain anomalies and overlaps. By constitutional convention, the Prime Minister is the leader of the party with the majority in the House of Commons. Ministers of State are recruited for the most part from members of the Commons with a smaller number from the Lords. The system of party political “whipping” has the result that (save in the case of occasional highly-publicised rebellions) the actions of the Legislature reflect the will of the Government of the day. The Judiciary is more demonstrably independent and some would argue that this is now the more so as a result of the steps to relocate the functions of the highest appellate court in the UK from the Judicial Committee of the House of Lords to an entirely distinguishable Supreme Court. This process has generated much political and constitutional heat. It was strenuously argued that the presence of the Law Lords in the legislative assembly of the House of Lords was offensive to the concept of separation of powers. However, defenders of the status quo pointed to the fact that their Lordships by convention scrupulously refrained from debate upon issues which were likely to come before them in their judicial function. However, Lord Bingham[6] is sceptical as to the purity of the function of the judiciary:

“The essential function of the court is then to interpret the law which it infers that parliament intended to make or would have made if it had addressed the point at all. This is not as legislative role, nor is it a purely interpretive role, since the court may have to do a good deal more than elicit the meaning of what parliament has enacted.”

The most glaring anomaly in relation to separation of powers in the UK has been the figure of Lord Chancellor. He has served as a member of the Executive by sitting in Cabinet, as a member of the Legislature by acting as Speaker of the House of Lords and as head of the Judiciary. It has been observed[7] that successive Lord Chancellors have relied upon the “characteristically English argument” that eminent public figures can by definition be trusted so that a formal separation of powers is not required. This argument was propelled to new depths of disingenuousness by Lord Irvine in 1999[8] when he suggested that the presence of the Lord Chancellor straddling all three branches of government actually safeguarded separation of powers by supplying a voice in the Executive and the Legislature that was able to speak out on behalf of judicial independence.

As with the rule of law, the European influence may be argued to strengthen rather than diminish separation of powers. Lord Irvine[9] argues that:

“Incorporation [of the European Convention on Human Rights] will enhance the judges’ power to protect the individual against the abuse of power by the state. We have a high quality of judicial review in this country. It has often rightly held the executive to account and improved the quality of administrative decision-making. So the concept of judges protecting the citizen and holding the executive to account is nothing new. What is new is that the judges will be given a framework by parliament within which to interpret the law.”

Thus it may be concluded that, notwithstanding the lack of a written constitution, the UK citizen is protected from capricious and unlawful acts of government by respect for the rule of law. This should not be regarded as an abstract philosophical concept: the principle operates within this jurisdiction to ensure that acts of government are transparent and predictable. When they fall short of these standards, the fact that there is a demonstrable independence of Judiciary and Executive (as has been seen the independence of the Legislature from the Executive is more questionable) means that the actions of government can be challenged and, if necessary, overturned. These various constantly evolving mechanisms ensure that the exercise of power within the UK constitution is accountable and limited.


Alder, J., General Principles of Constitutional and Administrative Law, (4th Ed., 2002)

Allen, M. & Thompson, B., Cases and Materials on Constitutional and Administrative Law, (7th Ed., 2003)

Barnett, H., Constitutional and Administrative Law, (5th Ed., 2004)

Bradley, A. & Ewing, K., Constitutional and Administrative Law, (13th Ed., 2003)



[1] Constitutional and Administrative Law, (13th Ed., 2003), Chapter 6

[2] Op. Cit., p.96

[3] [1994] 1 AC 377

[4] Quoted in Barnett, Constitutional and Administrative Law, (5th Ed., 2004) at p.77

[5] See Barnett, Op. Cit., p.79 et seq

[6] (1996/97) 7 King’s College Law Journal 15-16

[7] Alder, General Principles of Constitutional and Administrative Law, (4th Ed., 2002) at p.114

[8] Speech to the Third Worldwide Common Law Judiciary Conference, Edinburgh, 5 July 1999

[9] Constitutional Reform and a Bill of Rights, [1997] European Human Rights Law Review 483

Leave a Comment