Conventions, Prerogative Powers, and Constitutional Principles

Conventions’ main immediate function is to regulate the exercise of prerogative powers. It has been argued ‘[t]he case law on prerogative power [and conventions] exemplifies the tendency of the courts to interfere too far into matters which are not their concern, thereby taking a cavalier approach to general constitutional principles.’. Although constitutional conventions do give effect to “constitutional morality” and do accomplish this by regulating the use of the Royal Prerogative, it is submitted that the notion of “constitutional morality” can be distilled into the single specific objective of giving effect to the will of the people (what Dicey called the “political sovereign”) which supersedes parliament’s legal sovereignty. This insight is important because a clearer understanding of the normative function of constitutional conventions enables a more meaningful assessment of the extent to which they successfully carry out that function (their ‘effectiveness’). The efficacy of a constitutional convention is measured by how reliably it fulfils its fundamental objective: to ensure that the prerogative power it regulates is exercised in accordance with constitutional principles and the will of the people.

Constitutional conventions

Constitutional conventions are constitutionally significant non-legal rules which give effect to constitutional moralities/principles by regulating constitutional actors’ use of prerogative powers. There has been much debate about what the core defining features of conventions—as a conceptual category—are.

Constitutional conventions vary as widely in character, scope, and importance as the prerogative powers they regulate, making it difficult to analyse them as a single conceptual unit. A broadly orthodox (and roughly Diceyan) view identifies the following attributes.

First, the orthodox view states that conventions’ main function is to regulate the exercise of prerogative powers. Dicey believed that the primary function of most conventions is to prescribe or limit the way in which a prerogative power is used.[1] Per Dicey’s definition (approved by the court in GCHQ[2] and De Keyser’s[3]), the Royal Prerogative encompasses powers descended from the Crown’s original plenary authority which, while still legally exercised by the monarch, are now by convention exercised by the executive.[4] To the extent it may be said that there are ‘categories’ of prerogative power, this essay concerns itself with the government’s ‘prerogative executive powers’ (as opposed to the monarch’s ‘constitutional or personal prerogatives’),[5] which are the ‘powers which give executive authority to Ministers”.[6] Any action the executive can legally take without parliamentary input stems from the Royal Prerogative, including the power to deploy the armed forces.[7] Given the ‘elasticity’ of the prerogative and ‘the apparent limits [to] which [it] may be stretched by Ministers’,[8] its effective regulation is of paramount constitutional importance. Given the absence of direct input by the elected legislature, some kind of rule-based framework around the use of these powers is required to ensure that they are used in line constitutional principles, including accountability, parliamentary sovereignty, and the rule of law.

The previous Prime Minster Theresa May’s use of a prerogative power sometimes termed the ‘war prerogative’. This is the executive’s de facto legal power (legally held by the monarch, but which by convention the only ever uses as directed by Ministers) to deploy troops overseas without needing to consult Parliament.[9] This is among the executive’s most important prerogative powers, and therefore its effective regulation to ensure its use aligns with key constitutional principles is critical to the integrity of the UK constitution. A landmark House of Commons report listed Ministers’ principal executive powers, including “the deployment of armed forces overseas, including involvement in armed conflict or the declaration of war”.[10]

Second, the purpose of conventions is to give effect to constitutional principle and ensure that the exercise of the prerogative aligns with the will of the electorate. Conventions are widely thought to be bound up with “moral economy of our constitution”.[11] But what does this mean? How should we understand the claim, affirmed by the Canadian Supreme Court,[12] that conventions enforce (to use a Diceyan term) “constitutional morality”?

Sovereignty of the people

There are two main sources of the UK government’s legal powers: Acts of Parliament and the Royal Prerogative. In a constitutional democracy, a strong constitution will inter alia ensure that both powers are used in alignment with constitutional principle and the democratic will. Parliament’s power is held directly accountable through democratic elections, and legislation typically requires majority consensus between at least ~200-300 elected representatives to pass. But this is not true of the executive branch, where power is held by a far smaller number of individuals which means there is less accountability and a greater risk of abuse. While Marshall took ‘the executive’ to mean Cabinet Ministers as a group,[13] Hennessy describes the practice of deploying troops as ‘an intensely prime ministerial activity’,[14] showing that perhaps in this case power is even further concentrated.

When being interviewed by a House of Commons committee on the matter of the War Prerogative, Jack Straw and Lord Hague agreed that the legitimacy of the executive’s exercise of the prerogative—including the war prerogative—depends on the confidence of democratically elected Commons.[15] As Brazier notes, the government ultimately relies on popular support, and will always be held accountable to the electorate “sooner or later”.[16] While this may be sufficient in some cases, the potentially limitless adverse consequences that can come from a single deployment decision make ‘sooner-or-later accountability’ a less-than-reassuring safeguard against the potential abuse of the limitlessly destructive power to make war.

In regulating prerogative powers, the object of conventions is ensuring the prerogative is used in a manner compatible with the UK’s core constitutional principles, particularly the principle of democratic accountability not only to Parliament but directly to the electorate itself. It is argued on this point takes its starting point from Dicey, who viewed the bedrock purpose of constitutional conventions as being to give effect to the will of the people.

“[Constitutional conventions] have all one ultimate object. Their end is to secure that Parliament, or the Cabinet which is indirectly appointed by Parliament, shall in the long run give effect to the will of that power which in modern England is the true political sovereign of the State—the majority of the electors or (to use popular though not quite accurate language) the nation…No modern constitutionalist will dispute that the authority of the House of Commons is derived from its representing the will of the nation…[It is] the fundamental principle of our existing constitution that not Parliament but the nation is, politically speaking, the supreme power in the State…[T]he validity of constitutional maxims is subordinate and subservient to the fundamental principle of popular sovereignty”[17]

On Dicey’s view, Parliament is ‘only’ legally sovereign insofar as the courts treat Acts of Parliament as supreme law,[18] but remains ultimately subordinate to the higher-order political sovereignty of the “theoretically supreme legislature” of the citizenry.[19] In this way, constitutional conventions are maintained in order to protect parliamentary supremacy and thereby the “sovereignty of the people”.[20] The Canadian court observed that the “main purpose of constitutional conventions is to ensure that the legal framework of the constitution will be operated in accordance with the prevailing constitutional values or principles of the period”,[21] and that “the democratic principle: the powers of the state must be exercised in accordance with the wishes of the electorate” is the common “anchor” to which all constitutional conventions ultimately answer, or the “pivot” upon which all constitutional conventions turn.[22]

Constitutional Moralities

While an orthodox understanding of parliamentary sovereignty takes Parliament to have “the right to make or unmake any law whatsoever”,[23] Mark Elliott points out that while this is theoretically true, structural and political realities make it very unlikely that Parliament could ever “enact legislation which is utterly repugnant to the most fundamental [democratic] values” such as laws that discriminate on the basis of ethnicity, or the abolition of elections. The unthinkability of such an outcome complicates the traditional view of parliamentary sovereignty.[24] The “constitutional moralities” and justifications to which conventions give effect ultimately derive from the fact that, as Lord Templeman recognised, ‘the supremacy of power conferred on Parliament by the unwritten constitution of the United Kingdom [is] subject to quinquennial democratic control and to the daily force of public opinion’.[25]

This was similarly recognised by Lady Hale in Miller II: “Let us remind ourselves of the foundations of our constitution. We live in a representative democracy. The House of Commons exists because the people have elected its members”.[26] As Dicey notes, “the validity of constitutional maxims”—including parliamentary sovereignty, accountability, and the rule of law—are “subordinate and subservient to the fundamental principles of popular sovereignty”.[27] The key distinction here is that between “the rules which establish and vindicate a government’s power” and “the laws which assume the existence of the framework; and are made under it, because they prescribe the framework itself”.[28] While it is often said that the UKSC in Miller II gave effect to the principle of parliamentary accountability (which is not incorrect per se), upon closer inspection it becomes clear that the court recognised that ministerial accountability to parliament is, at base, a mere “means [by which] the policies of the executive are subjected to consideration by the representatives of the electorate”.[29] In this way, it is submitted that the Diceyan idea that conventions enforce “constitutional moralities” can be boiled down to the principle that, as Dicey himself stated, the ultimate object of conventions is to ensure that prerogative powers are only used in a way which gives effect to the will of the electorate.

In this way, Dicey argues that conventions create “the right to appeal to the people” by making it such that the violation of a convention will not be fatal if that violation is strongly supported by the electorate.[30] The political character of conventions’ enforcement depends on public opinion, making enforcement more flexible (or, depending on how you view it, less consistent). The flexibility of conventions can therefore be seen as a byproduct of the fact that the sanction for violating them is at the collective discretion of the public. If the public judge that a constitutional actor’s violation of convention is in the public’s interests, the electorate can exercise its collective discretion to withhold political opprobrium or even express popular support.

This can lead some to argue that our constitutional system or arrangement has become fractured and unable to deal with the types of problems our country faces such as, outbreak of COVID 19, leaving the EU, BREXIT and having staff shortages, a crisis with increasing illegal migration and off course the cost of living crisis and a stale economy. The executive along with Parliament and the courts appear to be caught up in a reactive cat and mouse game when the institutions of our state do not seem to be working together in harmony. Neil Parpworth,[31] sates:

“The debate as to whether or not there is a separation of powers in the UK constitution has...led to the establishment of two opposing camps. In the first of these camps can be placed the academic writers on constitutional law. The general consensus amongst them is that there is no separation of powers...In the opposing camp are the judiciary. On numerous occasions, senior judges have expressed the opinion that the UK constitution is based on a separation of powers.”

Conventions and the Courts

Third, conventions are not enforceable by the courts. Dicey identified two types of ‘rules’ which comprise ‘the law of the constitution’: traditional laws i.e. statutes and common law) relating to constitutional matters that are enforceable in the courts; and constitutional conventions that are not enforceable in the courts.[32] Following Dicey, the orthodox view (approved by the UKSC in Miller I)[33] draws a firm distinction between laws and conventions on the basis that conventions are not enforced by the courts.[34] Following Dicey, the orthodox view (approved by the UKSC in Miller I)[35] draws a firm distinction between laws and conventions on the basis that conventions are not enforced by the courts.[36] The court in Miller I were unequivocal on this point, noting that “the scope and manner of [conventions] does not lie within the constitutional remit of the judiciary’.[37] This view has its critics,[38] and even those who accept the ‘hard’ law/convention distinction have argued that judges may use conventions to clarify existing law.[39] The courts have certainly acknowledged the existence and importance of conventions.[40] and it seems plausible that courts have considered conventions as part of the broader factual background against which a decision is made.[41] As the Canadian Supreme Court pointed out, the reliance of conventions on precedent bears some semblance to common law.[42] It seems plausible that the courts in both Miller cases did effectively adjudicate a matter of convention, but did not take themselves to be doing so. This is evidenced by the fact that both Miller cases, particularly Miller I, are substantially reliant on conceptions of what, for example, ‘customary’[43] or ‘standard practice’.[44] Nevertheless, given the Supreme Court expressly declined to enforce a convention that was written into statute,[45] it seems reasonable to proceed on the assumption that the courts generally do not enforce conventions.

If conventions are not enforced by the courts, how do they bind constitutional actors? Conventions provide a “framework of political accountability”[46] that binds constitutional actors on pain of political opprobrium.[47] Conventions are “morally and politically, but not legally, binding”.[48] Jaconelli notes that conventions “lack the first requirement of a [legal] system…: an independent machinery of adjudication on questions of alleged violation”, concluding that conventions are therefore “self-policing”.[49] Jaconelli’s premise is correct, his conclusion assumes that convention depend entirely on the conscience of constitutional actors. With respect, this cannot be right. Such a view discount’s the ‘court of public opinion’ in creating political accountability. To argue that conventions are ‘self-policing’ suggests that there is no external force involved at all. The Canadian Supreme Court notes that “[t]he sanction for non-observance of a convention is political in that disregard of a convention may lead to political defeat, to loss of office, or to other political consequences, but will not engage the attention of the courts”.[50] Conventions are enforced by “the force of public opinion”.[51]

Some conventions are stronger than others

Cameron’s 2013 loss was said to be the ‘the first defeat for a British prime minister on a matter of war and peace since 1782’.[52] Rishi Sunak has said that ‘when it comes to the provision of military assistance to Ukraine, nothing is off the table’.[53] The Jennings Test is a useful heuristic for understanding the role of precedent, normative commitment, and constitutional importance impact the binding strength of conventions. But it may miss some of the nuance behind the strengths and weaknesses of the War Powers convention. Several precedents are often cited in support of the convention’s existence, but the difference in detail as to how the convention was understood in each instance calls into question whether these are a group of precedents supporting a single convention, or an assortment of individual precedents each supporting a slightly different convention. For example, in 2011 (and possibly 2018) it was unclear whether airstrikes were covered by the convention, but in 2013 it appeared they were included in the convention’s definition of “military deployments”. Likewise, there is some doubt as to whether only a debate is required, or whether a debate and a vote must be held. There also appears very little consensus as to what constitutes an “emergency situation” wherein the PM would not be obliged to wait for a parliamentary debate/vote.

The main problem is the lack of clarity surrounding the precedents. The fact that there is written evidence (via Hansard, and in official government documents) of the two dominant political parties consistently recognising ‘a convention’ regarding this issue makes it difficult to deny that a convention—or something like one—does not exist at all.

The War Powers convention is perhaps, at best, a “practice auditioning to be a convention”.[54] This is an important point, as it adds a whole extra layer of uncertainty which necessarily limits the binding capacity of the war powers convention in ways that are not true for conventions whose existence is well established and widely recognised. Any convention the existence or scope of which is unsettled provides constitutional actors with a strong basis on which to resist or undermine its application.

Dicey said that the reason he believes that constitutional conventions mainly regulate prerogative powers is due to the “ease and technical correctness with which such conventions may be expressed in the form of regulations in reference to the exercise of the prerogative”.[55] This feature is clearly absent in the case of the war powers convention, because the current uncertainty as to its scope literally defies articulation. One could read this as Dicey implying a criterion of clarity into his definition of conventions. This would make sense, as a lack of clarity as to the precise requirements a convention imposes

Should All prerogative powers in the UK should be placed on a statutory basis?

Given the almost limitless destruction that misuse of prerogative can cause, and its concentration in the hands of effectively one person, it is difficult not to conclude that the current conventions are an insufficient means for holding the executive to account in respect of its decisions. If prerogative power is not regulated by convention, could it be regulated by statute or common law?

Statute law and prerogative powers are sources of legal authority in the UK that public bodies can rely upon. In most contemporary society’s democracies, the only powers conferred upon governments are those granted through legislatures, parliaments, or written constitutions. The British constitution’s unique aspect is the extent to which diverse powers are accessible by the government, not granted by Parliament or a written constitution. Alternatively, these powers are the Crown’s ancient prerogative[56], deriving from arrangements prior to the 1689 Declaration of Rights and are enjoyed by government without interference from citizens or Parliament. The question then if the courts to ‘interfere too far into matters which are not their concern, thereby taking a cavalier approach to general constitutional principles’ should be rephrased to ask if ‘all prerogative powers in the UK should be placed on a statutory basis’. The central thesis is although an existing argument is that prerogative powers are excessively flexible in cases of state emergencies they should not be placed on a statutory basis; the benefits of placing prerogative powers on a statutory basis outweighs the drawbacks.

As mentioned, Royal Prerogative lacks a single definition. Nevertheless, Dicey referred to it as the residual portion of the Crown’s original authority (discretionary power) which the monarch or their appointed Ministers[57] can exercise. All powers available to the Crown, not based on the statute are prerogative, including powers held by the populace[58]. Le Sueur et al. (2013) noted key differences between statutory and prerogative powers. Prerogative powers Prerogative Powers are residual powers given to the Crown before the modern form of Parliament was developed. The Parliament’s role within Prerogative Powers is considered reactive (rather than proactive) as ministers account for how Prerogative Powers is exercised. Contrastingly, statutory powers are produced by the Parliament based on parliamentary debate, scrutiny, and subsequent approval of legislation[59]. In terms of their position in the hierarchy of legislation, Prerogative Powers are part of common law and are subject to abolishment or restrictions by Parliament whereas statutory powers are usually deemed the highest form of law, although their amendment is possible through subsequent Acts of Parliament[60]. 

To argue whether all prerogative powers in the UK should be placed on a statutory basis, understanding their applications in present society is pertinent. General prerogative powers[61] include powers concerning the legislature, powers pertaining to the judicial system (e.g. pardoning convicted offenders or lowering severity of sentences), powers concerning foreign affairs and powers relating to armed forces. Personal prerogative powers of the Sovereign include appointing a Prime Minister, prorogation and summoning of Parliament and Royal Assent to legislation. Prerogative during national emergencies is another form of Prerogative Power, as Lord Reid in Burmah Oil Company case established, this prerogative considers undertaking all actions during emergency which are critical for the conduct of war[62].

Several arguments can be made in favour of placing prerogative powers on a statutory basis. Firstly, the nature of Prerogative Power gives Ministers an incentive to conduct actions under the Royal Prerogative in the name of the Crown, given their sole power to negotiate, enter and ratify a treaty. Rawlings referred to prerogative powers as a deficiently democratic and outdated aspect of the British constitution, arguing for reformation with a view to placing Prerogative Powers on a statutory basis[63]. Ministers, particularly the Foreign Minister utilises considerable power in the context of treaty-making, as authority to make treaties is a Prerogative Power vested in the Crown exercised on Foreign Minister’s advice. One example is The Nationality and Borders Act 2022 brings about significant reforms to the asylum system in the United Kingdom by creating a two-tier asylum system that might result in those entering the UK illegally receiving less protection and assistance. There have been many concerning voices that some of the Act's provisions are, or will likely be against international law, harm people's ability to access justice, and have a detrimental effect on human rights.

In R (on the application of AAA and others) (Respondents/Cross Appellants) v Secretary of State for the Home Department (Appellant/Cross Respondent)[64] the Supreme Court has declared the scheme to be illegal. To circumvent the court decision, the UK government proposed the Safety of Rwanda (Asylum and Immigration) Bill. The Supreme Court held one fundamental tenet of international law is non-refoulement. The United Kingdom has accepted many international treaties that provide protection against refoulement for asylum seekers. The 1951 Convention on the Status of Refugees and its 1967 Protocol (referred to as "the Refugee Convention") and article 3 of the European Convention on Human Rights (referred to as "the ECHR"), among other documents, have provisions outlining these rights [19]–[26]. In response to the Supreme Court's decision, Home Secretary James Cleverly and Foreign Minister Dr. Vincent Biruta signed a joint treaty on December 5, 2023, enhancing the UK and Rwanda's Migration and Economic Development Partnership.

The legal status of treaties was acknowledged by Lord Oliver in Maclaine Watson v DTI [65] which established that even though royal prerogative involves making treaties, it does not amend the law because a treaty is not a part of English law unless legislation incorporates it into law. Courts acknowledged the Prerogative Powers available to ministers who can negotiate and sign a treaty as they deem appropriate. Lord Denning recognised that courts cannot challenge or question decision-making of Ministers because treaty-making power rests with the Crown and not courts[66]. Without parliamentary debate and scrutiny of a given treaty, which would be the case if Prerogative Powers are placed on a statutory basis, governmental ministers possess a strong incentive to serve self-interest or interests of their stakeholders[67].

Secondly, over time statutory powers replaced Prerogative Powers, thereby placing the Prerogative Powers in abeyance. Attorney-General v De Keyser’s Royal Hotel Ltd [68] established that Prerogative Powers cannot be used by the Crown when replaced with statutory powers, highlighting the superiority of statute law possessing the ability to overrule prerogative power. Statute law as supreme law is also reflected in Laker Airways Ltd v Department of Trade[69] which restricted the Crown’s ability to apply Prerogative Powers to counteract any statutory provisions, even when prerogative powers are still available to be used. The use of Prerogative Powers to promote lawful revocation was deemed unlawful by court as it was inconsistent with statutory rules established in Civil Aviation Act 1971. Roskill highlighted the limitation of prerogative powers in Laker Airways Ltd v Department of Trade[70] by stating that it provides the government an opportunity to achieve through the “back door which cannot lawfully be achieved by entry through the front”.[71]

There is a reason why statutory powers are considered superior to Prerogative Powers and why statutory powers over time have replaced some Prerogative Powers. Using Prerogative Powers, the British government can pursue narrow self-interest at the expense of wider national interests. One example is the former prime minister, Boris Johnson, admitted that on 20th May, 2020, during the national lockdown in the United Kingdom, a gathering of people took place in the grounds of 10 Downing Street. The disclosure follows outrage from the public over an email that was released that encouraged employees to “bring your own booze” and socialise at a time when they were not allowed to visit friends or family outside of their homes.  The events of that day were investigated, but the question of whether Downing Street officials followed one set of laws and regulations while the rest of us followed another was expeditiously settled in Sue Gray's report, a senior civil servant. During the two years of the epidemic, the UK experienced several legislation changes, making it hard to remember exactly what was allowed when. Should the prime minister or those close to him break the law, it raises the question of whether Prerogative Powers are still appropriate for contemporary society. Prerogative powers, contrary to enacted legislation, are not allowed to be exercised because they will translate into frustrating will of the Parliament[72]. Due to the importance of treaties and governmental decisions made under prerogative powers, it is undesirable that Parliament abstains from involvement in the process of ratification or application of Prerogative Powers due to their implications on day-to-day lives of British citizens.

Thirdly, even though Parliament routinely introduces new statutory powers conferred upon the government and public authorities, this is not the case with Prerogative Powers which government and ministers are unable to acquire. Instead, as established by Diplock LJ, the executive is only able to claim to possess Prerogative Powers if these powers had been acknowledged by common law and prerogative powers can never be broadened[73]. The outcomes of Burmah Oil Company and BBC v Johns highlight the viewpoint of courts in the UK that even where the Prerogative Power is extant, the Crown is unable to use such powers as in ancient times and Prerogative Power can never be broadened. The findings established by courts in these cases illustrate a shortcoming of Prerogative Powers that most Prerogative Powers are founded on incidents that occurred several hundred years ago which are now outdated, thereby less relevant in contemporary environments[74]. As Prerogative Powers have diminished in significance and relevance over time, there is a case for these powers in the UK to be placed on a statutory basis to ensure consistency in application of law. 

Alternatively, there is an argument against the statement that ‘all prerogative powers in the UK should be placed on a statutory basis’. Prerogative powers are argued to provide greater flexibility when the UK Parliament must deal with exceptional or highly unusual circumstances that have not been covered by previous statutory provisions. The Ministry of Justice acknowledged that PPs serve as a foundation for the UK Government to act outside the Civil Contingencies Act 2004 when faced with severe disruption or unconventional circumstances. In such situations, statutory powers have the drawback of lacking the necessary flexibility to provide a timely response and enacting a statute during this period can result in broad statutory power which may be undesirable[75]. This is supported by Bradley and Ewing[76], who asserted that during a significant emergency, it would not be possible for government to act outside the framework of Civil Contingencies Act 2004 thus reinforcing that some PPs should not be placed on a statutory basis. 

This article has analysed arguments in favour of and against the statement that there is a ‘tendency of the courts to interfere too far into matters which are not their concern, thereby taking a cavalier approach to general constitutional principles.’ Even though there is an argument against this statement that the flexibility of prerogative powers in cases of major emergencies means they should not be placed on a statutory basis, the essay concludes that benefits of placing Prerogative Powers on a statutory basis outweigh its drawbacks. Ministers or the government should not have an exclusive power to negotiate, enter and ratify a treaty because it could encourage them to pursue self-interest, whilst also contributing to circumstances that can translate into frustrating the will of the Parliament. Prerogative powers in the UK should be placed on a statutory basis to bring UK law in line with other major democratic societies whereby the powers conferred upon governments should only be those granted through the legislature, parliament, or a written constitution.

Regulating War Prerogative powers

When and why the government goes to war is a controversial issue on which reasonable people may disagree, but even avowed pacifists concede that a reasonably effective national defence capability is a ‘necessary evil’.[77] All prerogative powers submit to statute, all are potentially subject to convention (unless otherwise regulated by law), and some are justiciable. The practical realities associated with the use of a particular prerogative may limit the relative efficacy of one or more of these three mechanisms of accountability. The government’s use of the ‘war prerogative’, for example, is (a) generally non-justiciable, and (b) extremely difficult to regulate with statute.

The exigent, evolving, and secrecy-dependent nature of modern warfare makes the war prerogative almost uniquely ill-suited to effective statutory regulation. It is unclear how regulation by statute would work because it is so difficult to define what constitutes an ‘emergency’. Most acknowledge that any formalisation of parliament’s role in deployment decisions would need to be qualified by the exception that the government could deploy troops in an ‘emergency’ without Parliament’s pre-approval. Governing deployments by statute would also render the matter justiciable, opening the door to litigation and hampering the operational effectiveness of the armed forces. The unpredictable and changing nature of modern warfare, as well as the need to maintain military secrecy, makes it nearly impossible to craft a statutory regime that would enhance accountability without putting national security at risk. The flexibility of conventions, on the other hand, allow some measure of accountability without these problems.

The war prerogative cannot be regulated by the courts, as the judiciary have made it clear that they will not review uses of the prerogative concerning national security. The House of Lords has in confirmed that the decision as to whether deploy troops is the exclusive discretionary prerogative of the Crown.[78] Lord Roskill’s ratio in GCHQ made it clear that matters concerning national security and “the defence of the realm against potential enemies” are not reviewable by the courts.[79] Since this is not the case for most prerogative powers,[80] this is one of the ways in which the war prerogative presents a fairly unique regulatory challenge.

The Cabinet Code

Absent the availability of judicial review, the war power’s ill-suitedness to statutory regulation, and the uncertainty around the War Powers convention, what options for reform remain? Adam and Perry observe that while conventions have traditionally emerged organically or ‘bottom-up’, a new category of ‘top-down’ conventions has emerged in the form of documents like the Cabinet Manual and Ministerial Code. Adam and Perry view this as a negative development because it allows the executive greater control over the development of conventions, giving them the opportunity to ‘write their own rules’. The insight that conventions giving effect to the will of the people can be used to reframe ‘top-down’ conventions as a potentially potent tool of political accountability.

The convention of Ministerial responsibility (which in significant part involves following the conventions listed in the Ministerial Code) is supposed to act as a check on the executive. On the one hand, the numerous political scandals over the past few years could be cited as evidence that conventions are an ineffective means of regulating Ministerial behaviour. On the other hand, the fact that many the individuals concerned incurred substantial political (and personal) loss because of violating these conventions could be viewed as evidence of conventions working well.

It has been pointed out that the description in the Cabinet Manual lacks clarity. In a 2021 the House of Lords proposed that a revised Cabinet Manual should ‘reflect more accurately instances where the convention on consulting the House of Commons before…commit[ting] armed forces overseas has operated, including exceptions to those conventions and identifying the requisite authorities and precedents’.[81] A concordat between the UKSC and Ministry of Justice said that the Ministerial Code ‘may now be taken as the defining constitutional document on [the] Prime Minister and the Cabinet’.[82] McHarg argues that rather than deriving its power from its normative force per se, the extent to which a convention is binding is evidenced by people’s moral commitment to it.[83] From this, McHarg reasons that express agreement—a promise of sorts—to be bound by a particular rule could be considered strong proof of the requisite moral commitment.[84] While on the one hand, letting the government define its own rules creates obvious issues, on the other hand, the widespread outrage at news that Boris Johnson had re-written the Ministerial Code in an effort to evade accountability suggests that this the risks may not be as great as first imagined. Indeed, it could be argued that this indiscretion only made things worse for Johnson.

Renaming the Cabinet Manual something like the ‘Cabinet Code’ or writing all known conventions into a ‘Constitutional Code’ would more clearly signal to the public the significance of the breaking of a convention, and thereby strengthen the enforcement of those conventions. At present, much of the public may not understand the nature, role, and significance of conventions sufficiently to know when they are being broken. But everybody understands what a ‘code’ of conduct means. This is the reason Corbyn cited the Cabinet Manual in his criticism of Theresa May in the above quote—he recognises the power in being able to point to a key government document. Moreover, the drafting of these documents could be done with Parliament’s consultation, further increasing accountability.

Footnotes

[1] AV Dicey, Introduction to the Study of the Law of the Constitution (1915) (8th edn, Palgrave Macmillan UK 1979) 248 <http://link.springer.com/10.1007/978-1-349-17968-8> accessed 7 April 2023

[2] CCSU v Minister for the Civil Service (GCHQ) [1985] AC 374, 398

[3] Attorney-General v De Keyser’s Royal Hotel Ltd [1920] AC 508, 526

[4] Dicey (n 1) 247

[5] David Cameron, The Cabinet Manual (Cabinet Office 2011) para 3.34

[6] House of Commons, ‘Taming the Prerogative: Strengthening Ministerial Accountability to Parliament’ (2004) HC 422 para 4

[7] Cameron (n 5) 25

[8] Rodney Brazier, ‘Constitutional Reform and the Crown’ in Maurice Sunkin and Sebastian Payne (eds), The Nature of the Crown: A Legal and Political Analysis (Oxford University Press 1999) 356.

[9] Catherine Haddon, ‘Parliament, the Royal Prerogative and decisions to go to war’, 06 Sep 2013, Institute for Government < https://www.instituteforgovernment.org.uk/article/comment/parliament-royal-prerogative-and-decisions-go-war#:~:text=The%20power%20to%20commit%20troops,approval%20before%20taking%20military%20action.> accessed 19th December 2023

[10] House of Commons (n 6) 8

[11] P.A. Morton, ‘Conventions of the British Constitution’ (1991-92) 15 Holdsworth L Rev 114, 162.

[12] Re: Resolution to amend the Constitution (1981) 1 SCR 753 (Supreme Court of Canada) 881

[13] Geoffrey Marshall, Constitutional Conventions: The Rules and Forms of Political Accountability (Oxford University Press 1987) 53

[14] P Hennessy, The Prime Minister: The Office and Its Holders Since 1945 (London, Allen Lane, 2000) 103.

[15] ‘Oral evidence - The Role of Parliament in the UK Constitution: Authorising the Use of Military Force - 30 Apr 2019’ Q179

[16] Brazier (n 8) 356

[17] Dicey (n 1) 249–252

[18] ibid 249

[19] ibid

[20] ibid 250

[21] Canadian constitution case (n 12) 881

[22] ibid

[23] Dicey (n 1) 20

[24] Mark Elliott, ‘Parliamentary Sovereignty and the New Constitutional Order: Legislative Freedom, Political Reality and Convention’ (2002) 22 Legal Studies 340, 341

[25] Nottinghamshire CC v Secretary of State for the Environment [1986] AC 240, 265

[26] R (on the application of Miller) v Prime Minister and Cherry v Advocate General for Scotland [2019] UKSC 41 [55]

[27] Dicey (n 1) 252

[28] Sir John Laws, ‘Law and Democracy’ (1995) Spr Public Law 72, 87

[29] Cherry/Miller (n 26) para 46

[30] Dicey (n 1) 253

[31] Neil Parpworth,Constitutional & Administrative Law (10th edn, OUP 2018), 26

[32] AV Dicey, Introduction to the Study of the Law of the Constitution (1915) (8th edn, Palgrave Macmillan UK 1979) 81.

[33] R (on the application of Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5 [141–142]

[34] Dicey (n 1) 246; Miller I (n 32); see also Colin Munro, ‘Laws and Conventions Distinguished’ (1975) 91 LQR 218, 233, which was relied on in both Re: Resolution to amend the constitution [1981] 1 SCR 753, 783, and Miller I, [146].

[35] R (on the application of Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5 [141–142]

[36] Dicey (n 1) 246; Miller I (n 32); see also Colin Munro, ‘Laws and Conventions Distinguished’ (1975) 91 LQR 218, 233, which was relied on in both Re: Resolution to amend the constitution [1981] 1 SCR 753, 783, and Miller I, [146].

[37] Miller I (n 32) para 151

[38] See e.g. TRS Allan, ‘Law, Convention, Prerogative: Reflections Prompted by the Canadian Constitutional Case’ (1986) 45 The Cambridge Law Journal 305

[39] Marshall (n 13) 15

[40] See particularly Miller I (n 32) para 151: “we do not underestimate the importance of constitutional conventions, some of which play a fundamental role in the operations of our constituton…”

[41] ibid 146; Farrah Ahmed, Richard Albert and Adam Perry, ‘Judging Constitutional Conventions’ (2019) 17 International Journal of Constitutional Law 787, 803

[42] Canadian constitution case (n 12) 888

[43] Cherry/Miller (n 26) para 48

[44] Miller I (n 32) para 58

[45] ibid 148–151; Scotland Act 1998 (as amended by the Scotland Act 2016), s.28(8)

[46] Marshall (n 13) 2

[47] I Jennings, The Law and the Constitution (5th edn. 1959), p. 134.

[48] Marshall (n 13) 17

[49] Joseph Jaconelli, ‘Do Constitutional Conventions Bind?’ (2005) 64 The Cambridge Law Journal 149, 176

[50] Canadian constitution case (n 12) 853

[51] Dicey (n 1) 258

[52] Juliet Kaarbo and Daniel Kenealy, ‘No, Prime Minister: Explaining the House of Commons’ Vote on Intervention in Syria’ (2016) 25 European Security 28, 28

[53] Rishi Sunak Says ‘nothing off the Table’ When It Comes to Supporting Ukraine (Directed by The Independent, 2023) <https://www.youtube.com/watch?v=70MoTBVAT-k> accessed 9 April 2023.

[54] Philippe Lagassé, ‘The Crown and Government Formation: Conventions, Practices, Customs, and Norms’ (2019) 28 Constitutional Forum / Forum constitutionnel 2 <https://journals.library.ualberta.ca/constitutional_forum/index.php/constitutional_forum/article/view/29384> accessed 9 April 2023

[55] Dicey (n 1) 248

[56] Cox, Noel. "The gradual curtailment of the royal prerogative." Denning LJ 24 (2012): 1.

[57] Dicey, Albert Venn. An Introduction to the study of the Law of the Constitution, Tenth Edition, 1959, p 464

[58] Markesinis, Basil S. "The royal prerogative re-visited." The Cambridge Law Journal 32.2 (1973): 287-309.

[59] Le Sueur, Andrew, Maurice Sunkin, and Jo Murkens. Public Law: Text, Cases, and Materials 2nd edition. Oxford University Press, 2013.

[60] Banfield, Andrew, and Greg Flynn. "Activism or Democracy? Judicial Review of Prerogative Powers and Executive Action." Parliamentary Affairs 68.1 (2015): 135-153.

[61] Bradley, Anthony Wilfred, and Keith D. Ewing. Constitutional and administrative law. Vol. 1. Pearson Education, 2007.

[62] Burmah Oil Company (Burma Trading) Ltd. v Lord Advocate, [1964] 2 W.L.R. 1231, p 100

[63] Rawlings, Richard. "Legal Politics: The United Kingdom and Ratification of the Treaty on European Union (Part One)." Public Law (1994): 254-254.

[64] [2023] UKSC 42 

[65] Maclaine Watson v DTI [1989] 3 All ER 523

[66] Blackburn v Attorney-General [1971] 1 WLR 1037

[67] Palmer, Ellie. Judicial review, socio-economic rights and the Human Rights Act. Bloomsbury Publishing, 2007.

[68] [1920] AC 508

[69] QB 643

[70] [1977] 2 All ER 182

[71] Laker Airways Ltd v Department of Trade [1977] QB 643, p 722

[72] Gee, Graham. "The Political Constitution and the Political Right." King's Law Journal 30.1 (2019): 148-172.

[73] The British Broadcasting Corporation v Johns (HM Inspector of Taxes) [1965]: CA 5

[74] Breda, Vito. "The UK: identity-based constitutional claims in a parliamentarian system." Constitutional Law and Regionalism. Edward Elgar Publishing, 2018.

[75] Ministry of Justice, The Governance of Britain – Review of the Executive Royal

Prerogative Powers: Final Report

[76] Bradley, A. W., K. D. Ewing, and C. J. S. Knight. "Constitutional and Administrative Law. 16th edition. Pearson Longman: Harlow." (2015) p. 259

[77] Tanzil Chowdhury, ‘Taming the UK’s War Prerogative: The Rationale for Reform’ (2018) 38 Legal Studies 500, 500

[78] Chandler v DPP [1964] AC 763, 791

[79] GCHQ (n 2) 420

[80] GCHQ

[81] House of Lords Select Committee on the Constitution, ‘Revision of the Cabinet Manual’ (2021) HL Paper 34 para 5.36-5.38

[82] ‘Concordat Between: The Ministry of Justice and the Supreme Court of the United Kingdom’ (The Supreme Court, 30 October 2013)

[83] Aileen McHarg, ‘Reforming the United Kingdom Constitution: Law, Convention, Soft Law’ (2008) 71 The Modern Law Review 853, 861

[84] ibid