2.1.2 Constitutional Institutions Lecture

The Separation of Powers

Public law regulates the relationship between the state and its organs, and private citizens. Public law is a shorter way of describing constitutional and administrative law. Constitutional law is the law that provides a state framework and establishes its principle institutions and the interrelationships between these institutions. Administrative law confers the legal powers and legal duties of public bodies and authorities.

The separation of powers serves an essential democratic function, since it enables the three main powers of the state to act as a check on the absolute exercise of power. These powers are divided between three principle branches of government. Firstly, the legislative branch has powers to create legislation and to represent the views of the people. Second, the judicial branch is the systems of courts and tribunals who have powers to interpret legislation passed by the legislature and to adjudicate on legal disputes. Thirdly, the executive branch has the responsibility of making and implementing public policy.

In The Spirit of Laws, Montesquieu warned against the use of power in a 'tyrannical manner' if it was not divided between the three branches of government. Much of his observations were carried out within the court of George II in England, moving in political circles and formulating much of his work based on the English government of the time.

Modern democracies tend now to exist as a partial, or 'checks and balances', conception of the separation of powers, which includes the ability of one branch to involve itself in issues that are primarily the concern of another branch.

Although very few countries adhere rigidly to the separation of powers doctrine, most constitutional systems do attempt some form of demarcation between the legislature, executive and judicial organs of government to avoid abuse of power by any one of the three branches.

Separation of Powers and the Constitution

There are various different views as to whether the doctrine is part of the UK constitution. In Hinds v The Queen [1977] AC 195, Lord Diplock stated that he was certain that

'the basic concept of the separation of legislative, executive and judicial power...had been developed in the unwritten constitution of the United Kingdom'(at 212).

In The English Constitution (London, 1867) Bagehot argues that the

'efficient secret of the English Constitution may be described by the close union, the nearly complete fusion, of the executive and legislative powers".

There is a significant overlap in the work of the executive and the legislative branches, with the executive exerting a substantial influence over the work of Parliament. At the same time, there are examples where separation of powers is strictly adhered to, such as in relation to the independence of the judiciary.

In R v Secretary of State for the Home Department, ex p Fire Brigades Union [1995] 2 AC 513 a majority held that the Home Secretary had exceeded his powers in refusing to implement a statutory compensation scheme. The minority judgment held that since the legislation was not yet in full force, it was inappropriate for the court to intervene, making judicial intervention a breach by the judiciary of the separation of powers doctrine. The case illustrates how a different emphasis on one particular aspect of the separation of powers can lead to a different conclusion.

The Institutions - the Executive

The executive branch of the UK government is comprised of the Head of State, or monarch, the Prime Minister, the Cabinet, Secretaries of State, ministers of the Crown, departments of state, other public bodies, devolved administrative bodies, local authorities, the police and the military.

The Prime Minister is appointed by the Head of State; if appointed after a General Election, this takes place soon after the outcome is announced.

Figure 1: The UK Executive

The powers of the executive

Primarily the executive has a vast array of statutory powers afforded to it by Parliament. Since Parliament is unable to legislate for every eventuality, the Inquires Act 2005 makes provision for inquiries into matters of public concern.

The Prime Minister's powers come from the Royal Prerogative and statute. He or she has a role to advice the monarch on:

  • the exercise of all powers of entitlement which concern the government;
  • the appointment of all members of the judiciary, heads of the security services and senior officers in the Church of England.

The Prime Minister also appoints senior officers in the armed forces, and recommends honours or life peerages. The Prime Minister also makes decisions regarding the Cabinet, such as determining its size, controlling its agenda and creating and disbanding Cabinet Committees.

The Cabinet is chosen by the Prime Minister and appointed by the monarch. It functions to consider questions which concern the collective responsibility of government and are of critical importance to the public. The Cabinet determines the contents of the Queen's speech, the legislative timetable and the broad economic policy, which establishes the basis of the Chancellor of the Exchequers budget.

Standing and ad hoc Cabinet Committees are empowered by the Cabinet to deal with matters of current importance. Collective cabinet responsibility was endorsed in AG v Jonathan Cape [1976] QB 752, [1976] 3 All E R 484.

The Civil Service is required to act in a way that is independent of any political party. The advantage of this was said to be the element of stability despite political change in Parliament, Northcote-Trevelyan, Report on the Organisation of the Permanent Civil Service (House of Commons, 1854).


Devolution in the UK means that executive powers have been conferred upon executive organisations within Scotland, Wales and Northern Ireland.

The Scottish Government was established by part II Scotland Act 1998; it consists of the First Minister, the Scottish Ministers and the Scottish Law Officers. The Government of Wales Act 1998 (sections 52-55) established the Welsh Assembly. The Government of Wales Act 2006 establishes the Welsh Assembly Government, which is separate from the Welsh Assembly. The Northern Ireland Act 2000 suspended the Northern Ireland Assembly, but this was re-established by the Northern Ireland Act 2006, along with a Northern Ireland First Minster and other Ministers.

Local Government

Local Government in England consists of areas of counties, districts, and unitary authorities created by the Local Government Act 1972, as amended in 1985 and 1992. Greater London and the Metropolitan Police District were established by the London Government Act 1963, the Local Government Act 1985, the Police Act 1996, and the Greater London Local Authority Act 1999.

In Wales, the Local Government (Wales) Act 1974 established twenty-two Unitary Authorities in Wales.

Scotland in made up of twenty-nine Unitary Authorities and three Island Authorities, according to the Local Government (Scotland) Act 1974.

Northern Irelandconsists of the parliamentary counties of Antrim, Armagh, Down, Fermanagh, Londonderry and Tyrone and the parliamentary boroughs of Belfast and Londonderry. This is provided for in section 43(2) Northern Ireland Constitution Act 1973.

The Police

The police forces in the UK are part of the executive. The Police Act 1996 and the Police Reform Act 2002 contain provision for the organisation of the police forces and police areas in England and Wales.

The Institutions - Parliament (Legislature)

The UK Parliament is comprised of the House of Commons (or lower house) and the House of Lords (the upper chamber). Local voters in general elections elect members of Parliament within the lower house. Finally, the monarch is formally the head of Parliament, and is required to give royal assent to legislation.

House of Commons

Member of the House of Commons are elected directly by UK citizens.

The House of Commons as the representative assembly has come under criticism for its ability to represent the will of the people in the UK, in that:

  1. The current system of elections does not represent all parties equally within Parliament
  2. The House of Lords is unelected, however, it plays an important role in the making of the countries laws;
  3. There are insufficient women and ethnic minority MPs to represent the electorate.

There is no particular consensus on how MPs should represent their constituents.

House of Lords

The second and upper chamber is the House of Lords, whose members are peers. The vast majority of peers are life peers who are appointed to the chamber and remain members for their lifetime. This is provided for in the Life Peerages Act 1958, which also permitted women to sit in the House of Lords. The House of Lords also retains ninety-two hereditary peers, who have inherited their title. The number of hereditary peers reduced signification due to the passage of the House of Lords Act 1999; the current hereditary peers will remain as members of the Lords for their lifetime. Twenty-six bishops and archbishops (referred to as Lords Spiritual) of the Church of England are also members of the House of Lords until they retire from the roles in the Church.

The democratic legitimacy of the House of Lords has been drawn into question since they are not an elected body through the system of universal suffrage and cannot be removed by the electorate, since their role in the House of Lords is through appointment or inheritance. The House of Lords is going through a long-term period of reform, and a number of proposals have been made to improve its democratic legitimacy.

Functions of Parliament

The House of Commons Select Committee on Procedure (First Report, 1987) concluded that there were four main areas of Parliamentary responsibility. These include enacting legislation, scrutinising the executive, controlling public spending and address the concerns of their constituents. Parliament's legislative role is the enactment of primary and secondary legislation, which is said to respond to social, economic and political changes in society, which require new laws to be made.

The House of Lords and the House of Commons perform distinct functions in relation to the creation of legislation. This is known as a bicameral system with two chambers that perform different functions. The House of Lords acts as a check on the abuse of power by the executive, by blocking legislation that the House of Commons have proposed. The House of Lords may delay legislation; however, under the Parliaments Acts of 1911 and 1949, it cannot be prevented if the House of Commons agree that it should be passed.

The Institutions - The Judiciary

The primary role of the Judiciary is to adjudicate on legal disputes that are brought before courts and tribunals in the UK. The primary sources of law in the UK are legislation or Acts of Parliament and the common law. The judges' role is in the interpretation of legislation and in the development of the common law. Judicial independence is of primary importance, it has implications for its relationship with the executive and Parliament, and provides public confidence in the judge's ability to adjudicate on disputes in an impartial manner.

Judicial Review

One of the primary roles of the court systems is in holding the executive to account, by introducing accountability for the performance of public functions. This involves the checking, controlling and regulating of those functions.

The Senior Court Act 1981 and the Civil Procedure Rules are the most important legal instruments governing judicial review. In order to bring a claim for judicial review, claimants must illustrate at least one ground for judicial review is satisfied, or that a public authority has acted in a way that is incompatible with a human right included within the European Convention on Human Rights and Fundamental Freedoms 1950 (ECHR).

In Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374, three grounds for judicial review were elucidated:

  • Illegality
  • irrationality
  • procedural impropriety

The Human Rights Act

The Human Rights Act 1998 (HRA) gives effect to the ECHR in UK law.

  • When interpreting the Convention section 2HRA, a UK court must take into account any judgement, decision or declaration or advisory opinion of the European Court on Human Rights (ECtHR).
  • Section 3 HRA provides that courts must give effect to UK legislation in a manner that is compatible with the ECHR.
  • If not possible to interpret in accordance with section 3, section 4HRA enables the higher courts to grant a declaration of incompatibility stating that a statutory provision in inconsistent with the ECHR.

R v A (No.2) [2001] UKHL 25; [2002] 1 AC 45 illustrates how legislation introduced to promote complainants in rape cases from coming forward and reporting the crimes committed against them, and hence serving a public function, can still be overruled when the human rights of the accused are prioritised.

The European Union

Although the UK's membership within the European Union is currently in question, the EU is still of considerable relevance in UK law and governance.

The European Union as exists today was established in 1992 during a meeting of the heads of state or government of the Member States in which the TEU was signed at Maastricht in the Netherlands. The TEU made significant changes to the provisions of the preceding EC Treaty, including strengthening the powers of the European Parliament and establishing the foundations of the economic and monetary union.

The European Council

The European Council has no legislative function, but is to 'define the general political directions and priorities of the [EU]'(Art 15(1) TEU). It is made up on heads of state or government of Member States, its President, and the President of the Commission.

The Council of the EU

The Council is the hardest of the EU institution to place within the three branches of government advocated within the separation of powers doctrine. The Council considers legislation initiated by the Commission.

The Commission

The Commission carries out both executive and legislative functions. It is made up of a Commissioner from each of the Member States, who looks after a particular area of responsibility (e.g. trade and industry, competition).

The Parliament

The European Parliament consists of directly elected citizens of the Member States to exercise powers endowed upon it under the TEU and TFEU. In the UK, elections to the European Parliament are governed by the European Parliamentary Elections Act 2002. The Act provides for a system of proportional representation for election of MEPs. Article 14(2) of the TEU provides that the European Parliaments membership shall not exceed 750, in addition to the President of the Commission.

The Court of Justice of the European Union

The CJEU sits in Luxemburg and its membership consists of one judge per member state (Art 19(2) TEU). The rules of the court allow it to sit as the full court or in chambers of as a Grand Chamber. The primary function of the Court is to ensure that in the interpretation and application of the Treaty, the law is observed.

Legislative Functions

Executive Functions

Judicial Functions



Court of Justice of the EU



Court of Auditors

Figure 2: The separation of powers in the European Union

To export a reference to this article please select a referencing style below:

Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.

Current Offers