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Complete Public LawText, Cases, and Materials

Complete Public Law: Text, Cases, and Materials (5th edn)

Lisa Webley and Harriet Samuels
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p. 31. What is Public Law?free

p. 31. What is Public Law?free

  • Lisa WebleyLisa WebleyChair in Legal Education and Research, University of Birmingham
  •  and Harriet SamuelsHarriet SamuelsReader in Law, University of Westminster


Titles in the Complete series combine extracts from a wide range of primary materials with clear explanatory text to provide readers with a complete introductory resource. This chapter provides an introduction to public law. Public law regulates the relationships between individuals (and organisations) with the state and its organs. Examples include criminal and immigration law and human rights-related issues. Public law is made up of a number of key principles designed to ensure a healthy, representative, law-abiding country that strikes a balance between the needs of the state and the needs of its citizens. Each of these principles is discussed in turn: the rule of law, separation of powers, representative democracy, supremacy of Parliament, limited and responsible government, and judicial review executive action by the courts.

Key points

This chapter will cover:

What is public law and how does it differ from private law?

What is the constitutional and administrative law distinction?

Why is public law of relevance today?

What are the key principles of public law?

How can you make use of this book in your study of public law?


Welcome to Complete Public Law: Text, Cases, and Materials. This chapter aims to explain the structure of the book. It will introduce you to public law and set out how public law differs from private law, as many students have not thought in terms of ‘public’ and ‘private’ law until they study public law. It will also clarify constitutional and administrative law because some of you will study modules or courses that use these terms in their titles and may study the two separately. The chapter also aims to introduce the importance of public law to everyday life, as it can seem rather abstract and removed from students’ experience of the world. It will set out the key principles, in very general terms, so that you are familiar with how these fit together before you come across them in subsequent chapters. It will also provide some guidance on how to make use of the book and how the book is structured to help your learning.

1.1 What is public law and how does it differ from private law?

Most of the law subjects that you will study, and the legal situations with which you come into contact, will be based in private law. Private law regulates relationships between people, organisations, and companies. Examples include contract, tort, land, company, and employment law. Public law, on the other hand, regulates the relationships between individuals (and organisations) with the state and its organs. Examples include criminal and immigration law and human rights-related matters. Broadly speaking, ‘private law’ is an umbrella term for all areas of law that are essentially horizontal in nature, whereas ‘public law’ is the term that covers all areas of law that bring us into contact with state power and its application. Public law is essentially vertical in nature, as Figure 1.1 illustrates.

Figure 1.1 Private law and public law

If a case involves only individuals, companies, and other private organisations, then it is likely to be a private law matter. If it involves any of these along with a local authority, a public body or public authority, a government department, the police, or any other public official, then it may be a public law matter, p. 4depending on the nature of the facts. The distinction between public and private law is sometimes rather difficult to make in the UK because we do not have a distinctive public law system. Some countries, such as France, have a separate administrative or public law system, including a separate court system for this type of law. Indeed, it was argued by Dicey in the nineteenth century that the UK has no system of public law (although he recognised constitutional law as a type of law), and other academics continue to discuss the extent to which public law exists and, if it does, how it differs from private law.

M. Loughlin, Public Law and Political Theory (Oxford: Clarendon Press, 1992), pp. 2–4

What is it, then, that is distinctive about public law? Is public law a discipline? …

For some, it is sufficient to identify a particular set of institutional arrangements which may be treated as forming a discrete object of analysis. This seems to be the approach adopted by Professor Birks when he suggests that ‘few lawyers would deny that administrative law has a unity and an internal anatomy of its own, made explicit by many textbooks’.1 What is being suggested here, however, is simply that public law may be identified anatomically as a separate branch of legal study. While, as a result, particular concepts such as ultra vires or natural justice may have been developed, there is nothing in this argument which necessarily challenges this idea of the unity of law [that all law is similar—public and private alike].

Others, however, have gone further and have intimated that public law can be placed on an acceptable footing only by laying bare the skeleton of principle that provides it with a conceptual unity.2 This constitutes a more radical claim, since it implies that the subject possesses distinctive juristic foundations. Claims of this nature are sometimes made in conjunction with the argument … that the tradition of ordinary law has cast a long shadow over the study of public law … that public law is still secreted within … private law and has yet to develop its own philosophy and methodology.

There is, I believe, a more interesting premise from which to commence this inquiry. This is to start from the assumption that public law is simply a sophisticated form of political discourse; that controversies within the subject are simply extended political disputes. Since many argue that public law is rooted in its social, political, economic, and historical context this approach should ensure that our inquiry is embedded in the realities of the times.

1 P. Birks, An Introduction to the Law of Restitution (Oxford: Oxford University Press, 1983), p. 3.

2 See, e.g., T. R. S. Allan, ‘Legislative supremacy and the rule of law: democracy and constitutionalism’ (1985) 44 Cambridge Law Journal 111.

p. 5This extract is quite complicated because it is comparing and contrasting different ways in which academics have come to view public law. The first is as a set of laws that relate to the state and thus must be public law. The second is as a subset of private law, rather than as a distinct area with distinctive concepts underpinning it. The third, Loughlin’s view, is that public law is really a product of political negotiation and political ideologies. Many students studying public law say that they find the constitutional law part of the course or module to be similar to their previous politics studies; others ask why they are studying politics within a law degree because there seems to be very little ‘hard law’ in the constitutional law course. This may be because constitutional law, in particular, and many branches of administrative law too, are inherently political and are evidence of what different groups believe to be the role of the state, the extent of individual self-determination, and the differing values of groups within society. It is possible to organise and run a country in many different ways and the choices that are made in founding and running a state are the product of political decisions. Consequently, law and political theory are inherently intertwined in most public law courses, as are individuals’ and groups’ values and beliefs.

Constitutional law is also a product of a state’s historical development and, in many courses, history plays an important role in the constitutional law section of the course. Having said that, the scholar Dicey was of the view that the history of constitutional law was not of much use to students or lawyers. Indeed, he commented:

R. W. Blackburn, ‘Dicey and the teaching of public law’ [1985] Public Law 679, 681–2

… that the function of a trained lawyer is not to know what the law was yesterday … or what it ought to be tomorrow, but to explain what are the principles of law actually existing in England …

Lord Bingham of Cornhill disagrees with this view.

Lord Bingham of Cornhill, ‘Dicey revisited’ [2002] Public Law 39, 41

In the field of constitutional law such an approach seems to me not only anti-intellectual, but plainly misguided. Happily, as I think, it has increasingly come to be recognised that a lawyer without history, as well as literature, is a mechanic, and probably not a very good mechanic at that.

Consequently, we shall address historical issues in this book as and when they are relevant.

Summary points

What is public law and how does it differ from private law?

Public law is the study of the law that regulates the relationship between the individual and the state and organisations and the state.

There are different understandings of what the term ‘public law’ means.

Public law is linked to politics, history, and other disciplines, such as economics and sociology, and cannot be studied by merely referring to the text of the law.

You will come across competing theories in your studies and there is no one right answer—although there may be a number of wrong ones!

1.2p. 6 What is the constitutional and administrative law distinction?

In the past, the term ‘public law’ was used to describe all law that related to administrative law. In modern usage, and on some degree courses, ‘public law’ as a phrase is sometimes used as a short cut for the longer expression ‘constitutional and administrative law’. In this book, we use it to mean both constitutional and administrative law. It may be useful to explain what constitutional and administrative law are. ‘Constitutional law’ is the law that relates to the structure or framework of the state and the political and judicial institutions of the state. It includes the theories and principles that underpin the state. We cover constitutional law in the first fourteen chapters of this book. ‘Administrative law’ is the body of law that deals with the workings of the state, along with the statutory and common law powers and duties of government departments, local authorities, and public bodies and public authorities, which assist in the everyday life of the country. Administrative law may also regulate private bodies carrying out public functions. Constitutional law is the law that establishes the state and its institutions; administrative law is the law that these institutions use to run the country and to provide public services. We may use both constitutional and administrative law to examine whether the state and officials are operating within the law and where not to challenge their actions and hold them to account.

constitutional law

The law that provides the framework of the state and establishes the state’s principal institutions, e.g. Parliament, the government, the courts, and devolved legislatures and executives.

administrative law

The law that provides the legal power and the legal duties of individual public bodies and public authorities, e.g. local authority powers and duties, government departments, HM Revenue and Customs (HMRC), and the Student Loans Company.

Without constitutional law, it is difficult to see how we could have administrative law because administrative law is the law made by the state in order to allow it to run the country. But that presupposes that the state exists. Constitutional law must come first, so that there is a legitimate state—and this assumes that there is a state that is recognised by the people. In most instances, the state will include legislative, executive, and judicial organs that are imbued with power. Thereafter, they are involved in making the law, implementing the law, and enforcing the law, so that the state functions. But where does the power to establish the state come from, so that we may make constitutional law to establish it?

There are many different political and jurisprudential theories as to what power has been delegated by individuals (or taken from them), or who has the authority to rule, and under what circumstances and for what purposes. There are different schools of thought on the extent to which the individual’s delegation of power to the state is for all time or is time-limited or subject to conditions precedent (whether we can ever get our power back from the state and, if so, in what contexts). And further, on what we may expect from the state in return for handing over some of our power to it. Whole books have been written on these questions. There are two main political ideologies that underpin many of the explanations, the first being conservatism and the second being liberalism, and these ideologies shape the way in which one views the role and powers of the rulers or the state.

M. Loughlin, Public Law and Political Theory (Oxford: Clarendon Press, 1992), p. 63

Conservatism as a form of thought is traditionalist, is primarily concerned with the issue of authority and views the individual organically, as part of a social order. Liberalism is a rationalistic theory which has little regard for the past, is primarily concerned with liberty and is constructed on the assumption of the autonomy of the individual. Despite such important differences, these two political ideologies nevertheless share certain affinities with respect to their vision of law and government. It is the common core of shared understanding about law and government that provides us with an insight into the normativistic style in public law …

p. 7Our ideas about the relationship between the individual and the state, and consequently about public law, are shaped by our political ideology. Put crudely: do you believe in the authority of the state to regulate individuals’ behaviour according to a set of values (conservatism)? Or do you believe that the state has a duty to leave the individual to make his or her own moral decisions on appropriate behaviour in all but a small set of situations, even if that means that he or she is free to act in ways that you may find unpleasant or consider to be wrong (liberalism)? Your answer to this will determine some of your reactions to public law and to constitutional theory.

We are still little nearer to answering how states are established, however. Some states have been set up after a period of turbulence (war, revolution, independence) and have been founded after a process of consultation with the population or sections of the population. Others appear to have developed over time, without any individual having been asked to make a decision on how the state is to be set up, what values (if any) it should embody, and for what purpose it has been developed. It is not possible to say for certain whether constitutional law results from individuals in a country delegating some of their power to a central point on the basis that they believe that they are stronger as a collective rather than as individuals. Similarly, we cannot deduce whether individuals have entered into an explicit or an implicit social contract with a sovereign or with parliamentarians to provide power to them and to respect their authority to rule in return for certain protections or services. Equally, it may be argued that no decision was ever made to delegate or to hand over, or to assume power for particular purposes because in reality constitutional law has developed gradually over the centuries. This development may be the product of historical, political, social, and economic processes that have resulted in a form of law—constitutional law—being generally accepted and respected by citizens and by state bodies.

For undergraduate purposes, it is probably sufficient to understand that there are many views on how constitutional law was born and what its purpose is. Jurisprudence and legal theory courses will probably address this issue in much more detail. But you may want to consider this: can you imagine what life would be like in a place where there were no organised state? What do you think would be the strengths and the weakness if you and everyone else were to have total power over your own lives (with no laws to be enforced against you and no recourse to the law either)? Constitutional law provides the building blocks of the state, while administrative law provides the power to make it run according to the political proclivities of those in power and their values and beliefs. Between them, they give, legitimise, and limit the use of power, and our rights and duties as citizens.

Summary points

What is the constitutional and administrative law distinction?

Constitutional law is the study of the law that founds the state and sets up its institutions. It also regulates the relationships between the organs of the state.

Administrative law is the law that provides the power and imposes the duties on government departments and public bodies, so that they may fulfil the tasks that have been designated to them by the state.

Constitutional and administrative law are inherently political because they are based on different notions of how states should run and for what purpose.

1.3 Why is public law of relevance today?

‘Public law’ is a wide term that covers many disparate areas of law. At its highest level, it relates to the special powers that the state has to run the country—that is:

the power to make law, amend law, and repeal law;

the power to implement the law; and

the power to apply and enforce the law against us all (including against the state itself).

p. 8The power to implement the law—or perhaps, more specifically, to use the powers that have been bestowed on the state through legislation and the common law—is extremely wide-ranging. In UK terms, these include the power to deprive people of their liberty (in most instances, as a result of a criminal conviction or pending a criminal trial relating to a serious offence), to require individuals to do certain things as set out in law, to require us not to do certain things that are contrary to the law, to pay taxes, to make our children attend school or to be home schooled up to a set age, to enter and remain in the UK only if we have the appropriate entry clearances or we have been granted citizenship, etc. Figure 1.2 sets out a few of the areas that fall under the term ‘public law’ with which you may have come into contact so far.

Figure 1.2 Examples of public law matters

As you can see, public law pervades many areas of our lives. You will certainly have come into contact with public law issues already. We often take many areas for granted, such as human rights, the availability of welfare benefits, and the education and health services. For example, we have a legal right to access educational services to the age of sixteen or eighteen, depending on where one lives in the UK, and British citizens have a legal right to health care via the National Health Service (NHS). We may, perhaps, take the existence of these rights for granted because most of the time the state broadly respects human rights; this is a contested point, but, as a general rule, the UK government has a relatively good, if not unblemished, human rights record when compared worldwide.


You may wish to do some research on other areas of law that are covered by the term ‘public law’. The Public Law Project, a national charity that provides advice and assistance on public law matters for those whose access to advice and effective remedies from elsewhere is restricted, may be a good place to start.

Public law is not a static concept and it has changed over time. As indicated in section 1.1 above, Dicey was of the view that in the UK we did not have a system of public law per se, although it p. 9would be difficult now to find a serious commentator who agreed with that proposition. Indeed, the public-sector arena changes as different political administrations come and go in government. This affects the way in which public law and the theories that underpin it are framed. It has been argued by some commentators that public law today is very different from public law prior to the election of the Conservative government in 1979. As a result of reforms linked to a theory known as ‘new public management’ (NPM), it has changed the way in which some people view public law and the relationship between the individual and the state.

G. Drewry, ‘The executive: towards accountable government and effective governance’, in J. Jowell and D. Oliver (eds) The Changing Constitution (7th edn, Oxford: Oxford University Press, 2011), pp. 187–212, at pp. 196–8

Modernising Government: From Public Administration to Public Management

The election of the Thatcher Government in 1979 marked the beginning of a period of rapid and radical change in UK public administration. The process continued under … John Major—and was further developed and repackaged by Tony Blair’s Labour Government. Public administration has been displaced—at least in part—by a ‘new public management’ (NPM) which rejects traditional bureaucratic methods and structures in favour of market-based and business-like regimes of public service.1 The radical nature and extent of the NPM phenomenon is summarized by Owen Hughes:

… This is not simply a matter of reform or a minor change in management style, but a change in the role of government in society and the relationship between government and citizenry.2

… NPM has seen the growth of new relationships between the public sector and the private and voluntary sectors … The transformative process culminated, in 1988, in the launch of the radical Next Steps initiative … The Next Steps initiative has effected a transformation of the structure and the culture of the civil service, and has had a massive impact upon the organizational arrangements of government departments.3 It is only one aspect of the much wider NPM agenda …

… It might of course be argued that the arrangements for delivering public services—such as welfare, education, and health—are not a ‘constitutional’ matter at all, being concerned with administrative superstructure rather than with fundamental principles of government that are the essence of constitution. The Next Steps white paper, for instance, was not itself regarded as, or presented as, a ‘constitutional’ document, neither was the Blair Government’s Modernising Government white paper. However, both these documents … have important implications for ‘the changing constitution’ … The Modernising Government proposals consolidated and developed changing ideas about the relationship between the citizen, as a consumer of public services, and the state as service provider … And of course the Blair Government’s wider programme has featured major items of constitutional reform that both form a blackcloth to and feed into the micro-agenda of public service and public management reform: devolution, for instance …; the Freedom of Information Act 2000 …

1 There is a very large literature on the nature and development of NPM. See, in particular, O. Hughes, Public Management and Administration (3rd edn, Basingstoke: Palgrave Macmillan, 2003).

2 Hughes, n.1, p. 1.

3 See P. Dunleavy, ‘The architecture of the British central state’ (1989) 67(3) Public Administration 249 and 67(4) Public Administration 391.

Why does this matter? Shifts in the relationship between the individual and the state affect citizens’ rights and responsibilities and public bodies’ powers and duties, and how they must account for their actions and omissions. In turn, these shifts affect the nature of public services, their content, and delivery, as well as the way in which the courts address judicial review questions (administrative p. 10law cases). The purpose of administrative law has been hotly debated and differences in viewpoint have been categorised by Harlow and Rawlings (2009) (see the end-of-chapter ‘Further reading’) as ‘red-light’, ‘green-light’, and ‘amber-light’ theories of administrative law. Each colour corresponds to a different set of theoretical assumptions about the purpose of administrative law, the executive, and public body powers and duties, and the extent to which the courts should determine public law disputes. One’s understanding of whether the red-light, green-light, or amber-light theory outlines the most appropriate role of administrative law will colour the way in which you approach the study and practice of public law.

J. Goldring, ‘Administrative law: teaching and theory’ (1986) 15 Melbourne University Law Review 489, 495–6

(3) The Operation of Administrative Law

Harlow and Rawlings1 group those who have tended to theorize about administrative law into ‘red light’ and ‘green light’ theorists, though they concede the existence of ‘amber light’ theory. This characterization can be seen as a device to assist in understanding the effect of various approaches to administrative law. Dicey is a ‘red light’ theorist, in that he sees administrative law as placing restraints on what officialdom may do. To the extent that a theorist sees administrative law as establishing a system of limits on the exercise of governmental power, she/he is a ‘red light’ theorist. A ‘green light’ theorist, by contrast, perceives the law as an instrument by which policy can be implemented. McAuslan, in this taxonomy, is probably a ‘green light’ theorist. Others would be harder to classify …

These theories centre around the theorists’ perceptions of how the rules, practices and institutions operate. A major failing of many lawyers in the common law tradition is that they perceive administrative law solely from the standpoint of the private lawyer whose task it is to vindicate the right of the individual, or to protect the collective interest against those who, for reasons based on their interest of property, profit or ideology, seek to assert an individual right against it. Neither McAuslan,[2] nor Harlow and Rawlings, fall into this trap: they are respectively aware that the interest which is asserted by the State is not necessarily a collective interest but may just as easily be the interest of a private person or group on whose behalf the State has intervened. Therefore they do not see administrative law in terms solely of rights or interests but rather of a system in which various forces have some influence. While cases (and, to a lesser extent, statutes) which seek to enforce or protect rights are an important part of administrative law, they are not the only part. They are merely the part that is emphasized by the private law orientation of our legal culture …

Since administrative law deals with what might, in broad terms, be called ‘the administration’ (including, but not limited to, the state), it is important that lawyers realize that in addition to the legal culture with which they are most familiar there is also an ‘administrative culture’ which, in terms of forming ‘administrative law’ … is probably more important. Lawyers often tend to see rules, practices and institutions in the light of results in individual cases. Administrators are more likely to see them in terms of either policy implementation or mass decision-making, which may amount to the same thing …

1 Law and Administration (London: Weidenfeld & Nicolson, 1984), ch. 1.

[2] P. McAuslan, ‘Administrative law, collective consumption and judicial policy’ (1983) 46 Modern Law Review 1.

Goldring explains the basic distinction between red-light and green-light theorists as follows. The extract explains that red-light theorists consider the purpose of administrative law to be a means of controlling the state’s exercise of power to protect individual liberty. Green-light theorists consider administrative law to be a means of permitting the state to develop its policy agendas. Amber-light theorists, whom Goldring mentions, but whom he does not characterise, tend towards the view that law should control the exercise of executive discretion when that discretion has an impact on p. 11individuals’ constitutional rights. Some consider this to be a new direction for judges in judicial review cases in the UK, which is particularly relevant to cases that involve the Human Rights Act 1998 (HRA 1998). This will be considered in more detail in Chapter 14. Administrative law is part law, part procedural rules, and part policy. Some argue that this places administrative law in a very different category from private law and so it should be treated differently by lawyers as a result.

Tomkins (2002) (see ‘Further reading’) provides a more detailed explanation of the red, green, and amber-light theories of public law. Harlow and Rawlings’ book provides an extremely detailed analysis, to which you may wish to refer if you want to consider and develop your own view of the purpose of administrative law. However, it is probably sufficient for most undergraduate and graduate diploma students to know that there are fundamental differences in understanding about the purpose of constitutional and administrative law and that these, in turn, affect the way in which people approach politics and law, and the application of legal rules. These differences have an impact on the way in which public services are delivered and, indeed, whether a particular area is considered to be a public law or a private law matter. They also have an effect on the way in which judicial review judgments are framed, as you will see in later chapters, as judges try to balance the interests of different groups and to determine the appropriate limits on the exercise of public power.

Summary points

Why is public law of relevance today?

Public law is a term that covers many different areas of law.

It pervades many aspects of our everyday lives, from health and education to immigration and the environment.

There are different understandings about the purpose of constitutional and administrative law, linked to different political ideologies about the purpose of the state and the relationship between the individual and the state.

The different theories are evidenced by changes in public administration and changes in the way in which public services are delivered.

Recent governmental reforms have made changes to the structure of the state, which, in turn, have had an impact on public law.

The red-light, green-light, and amber-light labels are useful ways of categorising some of these differences to help us to understand the interplay between law and politics, the individual and the state, and policy and law.

1.4 What are the key principles of public law?

Public law is made up of a number of key principles, doctrines, or theories that are designed to ensure a healthy, representative, law-abiding country that has a balance between the needs of the state and the needs of its citizens. These principles will be discussed in detail in subsequent chapters. This section introduces you very briefly to the main principles and how they fit together, as follows.

The UK’s ‘unwritten’ constitution—this is less straightforward in a UK context than in many other countries because the UK has a constitution that has developed and evolved over many, many centuries. It is uncodified, in so far as we do not have one document of higher constitutional importance that sets out our rights and the constitutional structure and underpinnings of the state. It is heavily reliant on political mechanisms to constrain the executive, in the form of constitutional conventions. These are non-legal rules that are consequently not enforceable p. 12via the courts. Indeed, the constitution is made up of a range of legal and non-legal sources and is defined differently by different commentators. Some suggest that it has been made up of European Union (EU) law (which is considered by some to be hierarchically superior to UK law, noting the position of retained EU now that the UK has left the EU), which includes the European Convention for the Protection of Human Rights and Fundamental Freedoms, or European Convention on Human Rights (ECHR), UK primary and secondary legislation, the royal prerogative, the common law, precedent, constitutional conventions, and authoritative academic and practitioner sources. Others consider it to be restricted to domestic law and precedent. This is considered in detail in Chapter 3.

The rule of law—all are subject to law regardless of their status; in other words, no one is beyond the reach of the law, even if he or she is a state official. We all owe a duty to respect the law, both individuals and the state. The rule of law also covers a second concept, which is that the state should not exercise its power in an arbitrary fashion. This means that a public body should be consistent in its exercise of power and should not use any discretion unfairly to favour one individual or group of individuals over another. This is discussed in Chapter 4.

The separation of powers—there is some form of division between the three main powers of the state to ensure that a form of authoritarianism cannot become established and abuse the power entrusted to the state by the people. Leaders with absolute power are considered to be more at risk of abusing their power than are leaders whose exercise of power is checked or limited by other branches of the state. The independence of the judiciary is seen as particularly important to safeguard citizen’s rights and to ensure limited government. This is discussed in Chapter 5.

We live in a representative democracy—our elected officials have the role of representing the views of their constituents. Our elected representatives in Parliament—that is, Members of Parliament (MPs)—determine the law that is passed, and the executive develops law and policy so that it may implement its political agenda. In turn, MPs and appointed peers call the executive to account for its actions. This is discussed in Chapter 7 in relation to Parliament. Chapter 10 addresses devolution, the Scottish Parliament, and the Welsh and the Northern Ireland Assemblies.

The supremacy of Parliament—because the law is supreme and Parliament is the supreme law-making body, then the Westminster Parliament is considered to be supreme and may change or make any law that it wishes. Parliament should not be confused with the government, which is subject to Parliament and to the courts. Countries that operate a pure system of legislative parliamentary supremacy do not have a written constitution of higher constitutional importance against which primary legislation can be compared to review whether the primary legislation is constitutional and valid, or unconstitutional and invalid or void. Such countries, including the UK, do not have an entrenched bill of rights that can be readily asserted against Parliament. In other words, human rights may be restricted by Parliament and the courts cannot prevent Parliament from doing this because Parliament is legislatively supreme. This is in contrast to countries with written constitutions, which restrict the legislature’s power to enact law by delineating particular legal rights as ‘constitutional’ and therefore susceptible to amendment only if the constitution itself is amended. This is known as ‘constitutional supremacy’, rather than parliamentary supremacy. In states that operate a system of constitutional supremacy, it is usually for the courts to determine whether legislation is valid or invalid, as compared against the constitution. The UK attempts to protect individuals’ ECHR rights through the operation of the HRA 1998. Previous concerns about parliamentary supremacy in the context of EU membership are also considered. These matters are all discussed in Chapters 710 and also in Chapter 14.

Limited and responsible government—this is coupled with accountability to our representatives (parliamentarians) and to the electorate. This is one of the key mechanisms that limits the state’s opportunity to abuse its power. The uncodified British constitution is heavily reliant on political mechanisms to limit and restrain the government’s exercise of power and to call it p. 13to account for its actions. Constitutional conventions—non-legal rules that seek to limit the legal power conferred on the executive—are of particular importance. In addition, we shall consider the role of Parliament in calling the government to account for its exercise of power, as well as others, such as the Parliamentary Commissioner for Administration (PCA). This is discussed in Chapters 1113. There are many mechanisms of accountability and these are discussed throughout the book (see too Bamforth and Leyland (eds) 2013, referred to in the Further reading section below, for more on this area).

The judicial review of executive action by the courts—this is used to ensure that the executive’s use of power is legal, rational (and proportionate, in the case of human rights issues), procedurally proper, and conforms to the requirements of natural justice and does not breach the terms of the HRA 1998. Parliament is legislatively supreme, but it is important not to confuse this with the requirement that the executive must act within the law, either as provided by statute or by royal prerogative. The courts may review the executive’s exercise of power via a mechanism known as ‘judicial review’. This is discussed in Chapter 14 in overview, and then in detail in Chapters 1520.

Figure 1.3 oversimplifies the relationships between these theories and the state institutions, as you will discover during your study of public law. However, it illustrates that the key doctrine is the rule of law, which presupposes that the state is founded on the principle that the law prevails and that the state and citizens must act within the law or face court sanction. This is extremely important because, without it, the separation of powers would be largely ineffective: how does one ensure that different bodies stay within their legal remits if they do not respect the law that limits their powers and roles? Equally, the supremacy of Parliament would be relatively worthless if the law were not considered to be authoritative and legitimate: what use would it be for Parliament to make law if the population and the state organs were to ignore it and do what they wished, according to their own sets of rules or moral precepts? Limited and accountable government would also be difficult to achieve if the government were not to recognise the law as limiting what it could do, when, and under what circumstances. Consequently, although you may learn each of the theories in turn in separate chapters, lectures, seminars, and tutorials, they all overlap and support each other. It is also important to remember that there are different views on each of them: there is no conclusive right answer because theories or doctrines are made up of competing arguments based on a series of assumptions (with evidence to support them), rather than clear-cut descriptions of a set of accepted facts.

Figure 1.3 Relationships between constitutional theories and institutions

Summary points

What are the key principles of public law?

The first key principle is the rule of law, which means that the state is founded on the assumption that the law will be respected and that any individual or official may be brought before the court if there is evidence that he or she has broken the law.

The separation of powers means that the organs of the state are sufficiently separate so that the power of the state is not abused to the detriment of citizens.

Representative democracy indicates that parliamentarians have the power to make the law and to scrutinise the workings of government because the electorate has elected MPs to perform these functions on its behalf (as its representatives).

Parliamentary legislative supremacy means that Parliament has the supreme power to make, amend, and repeal laws on our behalf.

Finally, limited and responsible government means that the executive must obey the law and may be judicially reviewed and held to account by the courts and tribunals if it is believed that the executive has acted illegally, irrationally, or procedurally improperly, has broken the rules of natural justice, or has breached the Human Rights Act 1998.

1.5p. 14 How can you make use of this book in your study of public law?

We hope that this book will provide you with a clear understanding of each of the topics that it seeks to address. We have tried to keep the content as simple as possible, while balancing simplicity with the need for sufficient detail to allow you to reach an appropriate level of understanding at undergraduate or graduate diploma level. Many of the chapters have a common structure: they provide some background on the area, an insight into its historical development, and an explanation of the competing theories or judgments, as well as evidence of them in the extracts that we have chosen. Each chapter will set out the general principles of the topic and address each one in turn. Extracts provide you with p. 15the evidence that backs up the points that are being made. Sometimes, the evidence will be the text of the law; sometimes, it will be judicial opinion on the law; sometimes, it is academic opinion. In other instances, you will read extracts from interest groups, or we will have included extracts from government proposals that indicate areas of concern or propositions for change. Some of the extracts are quite long and they are, at times, complicated. You will usually find an explanation after an extract that highlights the salient points. In addition, the chapters are organised a little like a diamond: at the beginning of each chapter, you are told what will be covered and the general principles that relate to the topic. The middle (and wider part) of the chapter is split down so that each of the general principles has a section dedicated to it. At the end of the chapter, we return to a summary of the key principles as a form of revision. Most of the chapters contain bullet-point summary boxes at the end of long sections, to summarise the essential points that have been made, and there is a summary at the end of each of the substantive chapters that highlights the main points for the topic. We hope that this structure will help you to see both the overview and the detail of each of the areas that you are studying. There are self-test questions at the end of each substantive chapter and there are additional online resources so that you may practise and test your knowledge further, if you so wish.

We have often been asked by students how they should approach their reading, which is a difficult question to answer because there are as many approaches as there are people. However, in response to repeated questions on this, we have set out a few different ways in which you may wish to make use of this book, in case any of them are helpful to you.

One approach might be to write down the key principles that are set out in the summary box at the end of each chapter, and then add in the detail for each of the principles underneath each one, once you have read each section that relates to the principle.

Another approach might be to draw a diagram of how the general principles fit together, along with each principle’s components—a little like Figure 1.3 of the key principles of public law that appeared earlier in the chapter.

Another, more traditional way of approaching your reading is simply to make notes as you go along and largely to ignore the material that we have put in the summary boxes, but to develop your own instead. The summary boxes contain our views on what we consider to be important, but you may come to different conclusions. Also, the process of developing your own summary boxes or bullet-point lists may be a form of revision that helps you to make links between the topics and between the principles and which deepens your understanding.

Good luck with your public law studies, however you choose to make use of this book.



Draft a brief definition of the term ‘constitutional law’ and one for ‘administrative law’.


Make a list of areas of public law with which you think you have come into contact.


What are the key principles of public law and how do these link together?


What role does political stance or ideology play in our understanding of public law?


How will you make use of this book as part of your public law/constitutional and administrative law studies?

For guidance on how to answer these questions, and to test your knowledge with self-test questions, visit the online resources.

p. 16Further reading

  • Bamforth, N. and Leyland, P. (eds) Accountability in the Contemporary Constitution (Oxford: Oxford University Press, 2013)
  • This is a very detailed and high-level book made up of a series of essays written by leading public law scholars. It sets out the underpinnings of public law and the different ways in which accountability plays such an important role in contemporary constitutional thought and practice.

  • Lord Bingham of Cornhill, ‘Dicey revisited’ [2002] Public Law 39
  • This article explains how Dicey’s approach to public law remains relevant today and why his theories are often a starting point for academic debate.

  • Blackburn, R. W., ‘Dicey and the teaching of public law’ [1985] Public Law 679
  • This article sets out how Dicey’s approach to defining public law and his mode of teaching public law has shaped our current understanding of what is public law even today.

  • Drewry, G., ‘The executive: towards accountable government and effective governance ’, in J. Jowell and D. Oliver (eds) The Changing Constitution (7th edn, Oxford: Oxford University Press, 2011), ch. 7
  • This edited collection chapter explains the changing face of public administration; the less-than-clear-cut separation between the executive, legislative, and judicial functions; and the influence that NPM has had on the way in which public services are delivered and the approach to government and governance. The Changing Constitution is now in its ninth edition, but you will need to read the seventh edition to access Drewry’s chapter.

  • Feldman, D., ‘The internationalization of public law and its impact on the UK’, in J. Jowell and C. O’Cinneide (eds) The Changing Constitution (9th edn, Oxford: Oxford University Press, 2019), ch. 5
  • This edited collection considers the way in which public law in the UK is being shaped by global currents and the influence this is having on public law in the UK.

  • Harlow, C. and Rawlings, R., Law and Administration (Law in Context) (3rd edn, Cambridge: Cambridge University Press, 2009)
  • This book provides a very detailed explanation of the red-light/amber-light/green-light theories of administrative law and how these structure our understanding of what is administrative law.

  • Tomkins, A., ‘In defence of a political constitution’ (2002) 22(1) Oxford Journal of Legal Studies 157
  • This article provides an explanation of the importance of politics within the British constitution and also the political mechanisms that check and balance the legal power that has been conferred through the legal sources of the constitution.

    You may also want to read the related blog posts on the UK Constitutional Law Association’s site.