The Attorney General is one of the most powerful and influential officers in the British Constitution. They are the chief adviser of the Crown on points of law and the chief counsel for the government in legal proceedings. They also have an important role in the machinery of criminal law enforcement in England & Wales and a wide range of prerogative and statutory powers that they exercise in their capacity of guardian of the public interest. 

In a thoughtful essay published last week, Mr Dane Luo offered a rigorous analysis, and critique, of the current law governing the justiciability of the Attorney General’s public interest powers. Mr Luo made several arguments why the Supreme Court should consider revisiting the doctrinal status quo. One contention was that the lack of reviewability of the Attorney General’s statutory and prerogative powers was conspicuously out of step with “modern developments in judicial review”. Another argument made by Mr Luo, the argument I want to address in this post, is that without judicial review “there is a risk that the Attorney-General could abuse an unbridled discretion. This could mean that powers intended to be exercised in the public interest could lawfully be exercised for private benefit or other improper purposes.”

I think this argument is overstated. Mr Luo correctly notes that as a Minister the Attorney General is subject to the usual processes of parliamentary scrutiny. But what is missing from the contention that judicial review is required to prevent the abuse of the Attorney’s “unbridled discretion”, is consideration of the specific constitutional convention that helps structure and discipline the exercise of the Attorney’s public interest and criminal law enforcement powers. Even without judicial review, there are powerful and deeply ingrained constitutional constraints on the Attorney’s (admittedly broad) criminal law and public interest powers.

Criminal law enforcement and public interest powers

As first law officer of the Crown, the Attorney General is primarily responsible for law enforcement in England & Wales. All criminal prosecutions in England & Wales are taken in the name of the Crown and, as a matter of formal constitutional doctrine, the Attorney General is the Crown’s principal public prosecutor. They enjoy quite considerable prerogative powers in respect of the conduct of criminal prosecutions. In his speech in Gouriet v Union of Post Office Workers [1978] AC 435 Viscount Dilhorne (Attorney-General from 1954 to 1962) outlined the broad prerogative powers the Attorney General has in respect of criminal enforcement:

“The Attorney-General has many powers and duties. He may stop any prosecution on indictment by entering a nolle prosequi. He merely has to sign a piece of paper saying that he does not wish the prosecution to continue. He need not give any reasons. He can direct the institution of a prosecution and direct the Director of Public Prosecutions to take over the conduct of any criminal proceedings and he may tell him to offer no evidence. In the exercise of these powers he is not subject to direction by his ministerial colleagues or to control and supervision by the courts.”

While the formal constitutional powers of the Attorney General remain untouched, the last century has seen an unmistakable trend of successive Attorneys General (with the tacit consent of successive governments) voluntarily and publicly placing major limitations on their powers to initiate, direct, or discontinue individual prosecutions. 

In recent years the Attorney General’s Office and prosecutions services (Crown Prosecution Service and Serious Fraud Office) have collaborated to elaborate on the nature of the Attorney’s statutory superintending functions over the prosecution services. The framework agreements between the Attorney General’s Office and the prosecution services cement and publicly outline practices that had been developing over the latter stages of the twentieth century: that it is only in exceptionally limited circumstances that the Attorney General will get involved in operational decision-making in the conduct, or continuation, of individual prosecutions. The current framework agreement between the Attorney General’s Office and Crown Prosecution Service, for example, states that “[E]xceptionally, and only where in the Attorney General’s opinion it is necessary to do so for the purposes of safeguarding national security, the Attorney General will consider the exercise of their power to issue a direction that a prosecution is not started or not continued”. The Attorney General will also, very occasionally, exercise their prerogative powers to issue a nolle prosequi and stop a prosecution for humanitarian grounds, for example when a defendant is gravely ill. 

While the Attorney General has voluntarily set aside using their prerogative power to institute or discontinue prosecutions in (the vast bulk of) individual cases, there are still many statutes Parliament has enacted which provide that the Attorney’s consent must be granted before a prosecution can continue. There is no discernible theme or intelligible thread that connects the type of offenses subject to the Attorney’s consent, which range from offences under the Agriculture and Horticulture Act 1964 to the War Crimes Act 1991. Several Attorneys General have floated principled arguments justifying the need to secure their consent in some matters, arguing that they serve as a “gatekeeper to the courts”, which serves as “valuable protection from an oppressive state” and overzealous prosecutors.

The Law Officers also have a range of prerogative and statutory powers that, when exercised, are carried out in their role as ‘guardian of the public interest’. Many of the Law Officers’ responsibilities that come under the umbrella of this impressive title find their historical home in the Crown’s foundational duty, as the source and fount of all justice in the realm, to keep the peace, protect the interests of their subjects, and ensure the due administration of justice.

As just discussed, the Crown’s chief Law Officers enjoy considerable authority over the conduct of prosecutions. They also enjoy authority to take a range of actions that are closely related to upholding the law and ensuring the effective functioning of the justice system. In this context, they have long had authority to initiate proceedings for contempt of court or to restrain vexatious litigants from wasting judicial time and resources or oppressing other litigants. In recent years, Attorneys General have taken to issuing advisory notices to the public in respect of high-profile legal proceedings warning of the need to avoid prejudicing the administration of justice and noting that the Attorney General’s office will be monitoring coverage of proceedings. In other words, they are an admonition issued urbi et orbi for would-be commentators to tread carefully.

They also enjoy prerogative authority to do things like grant undertakings at statutory inquiries about the admissibility of evidence in future proceedings, appoint so-called special advocates, which are counsel appointed to represent the interests of individuals in certain cases involving sensitive material which cannot be disclosed in the ordinary way, and statutory authority to grant leave to seek to have an inquest determination quashed before the High Court, or refer a criminal sentence to the Court of Appeal for assessment about whether it is unduly lenient.

The Crown has a historical role as parens patriae – father of the people – and responsibility to protect people’s lawful rights and interests; with special responsibility for those who cannot vindicate their own entitlements. The Attorney General is the officer that exercises this historical duty on behalf of the Crown. This is the foundation of the Attorney General’s duties in respect of charities where, simply put, their role is to ensure the sound and proper administration of charitable bequests and help the public to have trust and confidence in charities and charitable endeavours. 

These are very considerable powers that are not, for the moment at least, subject to ordinary judicial review principles. But it would be myopic to regard these powers as devoid of constitutional checks simply because they cannot be scrutinised by a judge; for their exercise is embedded in a web of constitutional convention and political practices that curb the scope for their arbitrary exercise. 

Constitutional conventions structuring the Attorney General’s discretionary powers

One major check on the Attorney General is that, in exercising their criminal law enforcement and public interest authority, they are constitutionally bound to act independently and quasi-judicially, free from pressure or direction from government, and without regard to personal or party advantage. This convention was settled in the aftermath of the famous 1924 Campbell prosecution.  

Prior to this case, there was lingering ambiguity about whether the Cabinet could properly instruct the Attorney General how to exercise their prosecutorial or public interest powers, including for explicitly political or partisan purposes. For much of the Law Officers’ history, whether and how they acted was entirely subject to the will of the Monarch. Long after the development of responsible ministerial government, ambiguity remained over whether the Attorney General could be instructed by the Prime Minister on how to use their powers. As Marshall explains, some took the view that “[S]ince the prerogative of the Crown is exercised by convention on the advice of Ministers, there seems nothing inherently improper in the Ministry’s forming a collective view about the use of the prerogative in a particular case and directing the Attorney-General to comply with it.” It took the seismic fallout from the Campbell affair to definitively settle the constitutional independence of the Attorney General in respect of his public interest and prosecutorial functions.

In that case, Sir Patrick Hastings – the Attorney General of the first Labour Government of Ramsay McDonald – began and then subsequently discontinued the prosecution of one Mr Campbell, a newspaper editor of the communist periodical the Worker’s Weekly, for incitement to mutiny in respect of an article his paper had published about the armed forces. The relevant article urged soldiers to disobey any orders demanding they engage in strikebreaking. While Mr Campbell was not the author of the article, he permitted it to be published and would not retract it. 

News of the prosecution caused anger amongst some Labour backbenchers, who saw it as excessive to prosecute for an article simply discouraging soldiers from allowing themselves to be improperly used in industrial disputes. If this did not already unnerve Sir Patrick, he was further informed that Mr Campbell was a highly decorated and severely wounded WW1 veteran. Concern grew within Labour circles about the wisdom of the prosecution, its chances of success, and the wider social impact it might have. Soon after discussing the issue with the Prime Minister and other members of Cabinet, Sir Patrick gave the order to discontinue the prosecution.  

The discontinuance was seized upon by the opposition, and the central matter of controversy became whether the Attorney had been pressured in any respect by government colleagues to discontinue the prosecution he had started. The Prime Minister denied having any involvement in the decision in the Commons, prompting the opposition benches to say he misled Parliament. No-one doubted the Attorney had the constitutional power to discontinue a prosecution, but there was uncertainty over whether this was a power subject to direction through collective ministerial responsibility, or whether it could be properly used on foot of party-political considerations. In JLJ Edwards’ detailed study of the case, he concludes that McDonald displayed an “appalling lack of candour” to the Commons, as the evidence suggests the Cabinet did take the official position that the Attorney should halt the prosecution and that, in future matters, the Cabinet’s sanction was required by the Attorney before he could prosecute an offense with a political character. 

The ensuing political turmoil collapsed the government and, whatever the position before the affair, swiftly solidified the constitutional convention that the Attorney General must make decisions in respect of criminal prosecutions free from any political or partisan pressure or considerations of party politics. 

Some years later, in 1951, then Attorney General Hartley Shawcross QC sought to definitively outline the requirements of this constitutional convention to the House of Commons. Prior to making his statement to the House, he circulated a draft for comments, including to several former Law Officers and the Director of Public Prosecutions. His correspondents, who ranged across political parties, were in complete agreement with his proposed remarks.

In his statement to the Commons, the Attorney outlined what later became known as the ‘Shawcross principles’. They provided that:

‘the true doctrine is that it is the duty of an Attorney-General, in deciding whether or not to authorise the prosecution, to acquaint himself with all the relevant facts, including, for instance, the effect which the prosecution, successful or unsuccessful as the case may be, would have upon public morale and order, and with any other considerations affecting public policy. In order so to inform himself, he may, although I do not think he is obliged to, consult with any of his colleagues in the Government… On the other hand, the assistance of his colleagues is confined to informing him of particular considerations which might affect his own decision, and does not consist, and must not consist, in telling him what that decision ought to be. The responsibility for the eventual decision rests with the Attorney-General, and he is not to be put, and is not put, under pressure by his colleagues in the matter.’  

Although the Attorney spoke in the context of prosecutorial decision making, the core thrust of the Shawcross principles are widely understood to apply to the full spectrum of their public interest functions. 

The heart of the convention is the principled line it draws concerning the proper role of political and personal considerations in prosecutorial and public interest decision-making, setting clear expectations for the Attorney and their cabinet colleagues. The chief consideration which Shawcross insisted was “altogether excluded… is the repercussion of a given decision upon my personal or my party’s or the government’s political fortunes; that is a consideration which never enters into account”. All of which is to say that the Attorney General’s powers are always constitutionally bounded. Whether he is considering a consent for prosecution, a request to bring proceedings to have an inquest determination quashed, or to have a nolle prosequi entered, the Attorney General is constitutionally required to act independently of any political pressure, partisan considerations, or improper personal considerations. These are constitutional considerations over and above those ethical rules that attend to the conduct of all Ministers.

Policing and enforcement of the Convention

That these conventions are taken very seriously is perhaps best reflected in the dearth of incidents like the Campbell case, where there was a well-founded allegation that the Attorney General had acted following improper political pressure or on the basis of partisan considerations. We can also take comfort in the fact there are no reported or alleged cases (that I can recall) of an Attorney General exercising their powers for a criminally improper personal purpose, like bribery (although we might say this would be an issue best dealt with by criminal, not constitutional law).

JLJ Edwards’ magisterial second study of the Law Officers, The Attorney General, Politics, and the Public Interest, goes into considerable detail about several political controversies sparked by Attorneys General exercising their discretionary powers, whether it be to decline to prosecute a case (for example, the Leila Khaled plane hijacking and Rhodesia Oil Sanctions cases), to grant their fiat to a private citizen to seek an injunction to prevent a breach of the law (Gouriet), or to seek an injunction to prevent publication in breach of cabinet confidentiality (the Crossman diaries case). In these cases, even though the Attorney General could fairly show that they clung tightly to the Shawcross principles and could reasonably demonstrate they were acting bona fide in the public interest, Edwards highlights that their discretionary powers proved to be a political flash point. In each instance, even the faintest whisper that an Attorney General might be breaching the Shawcross principles inevitably led to sustained parliamentary scrutiny, assessment, and judgment about how their discretionary powers were used, which underscores the long-standing seriousness with which the convention has been held.  

A relatively recent example of the controversy the exercise of the Attorney General’s discretionary powers can fuel can be seen in the aftermath of the 2006 decision of the Director of the Serious Fraud Office to halt an investigation into allegations that Saudi officials were bribed to win an order for a British arms firm. The decision not to prosecute was officially taken by the Director, after conducting a “Shawcross exercise” with rounds of consultation with the Attorney General, Prime Minister, and other Cabinet officials. 

The Prime Minister and other Ministers relayed, through the Attorney General, what they considered the dangerous national security implications of a prosecution. The Director said he made his final decision based on considerations of the public interest, in particular the serious national security risks that a trial could pose because of its impact on UK-Saudi security and intelligence relations. Then Attorney General Lord Goldsmith told the Director he agreed with the decision not to prosecute, and informed Parliament.

Controversy soon erupted over whether the government had jettisoned its commitment to anti-corruption law to placate Saudi officials. There was additional controversy over whether the Attorney General and the Prime Minister had pressured the Director to discontinue the prosecution, an allegation all actors strenuously denied. There was also controversy over whether the Attorney General would, hypothetically, have used his prerogative authority to order the Director to discontinue the prosecution, should the latter have wished to proceed. 

The idea that the Attorney might allow political pressure from his cabinet colleagues to influence his superintendence functions or that he could have allowed such pressure to shape the possible exercise of his discretionary prosecutorial powers, motivated parliamentarians to subject the whole episode to searching scrutiny. The question of whether the Attorney had acted consistently with the Shawcross principles was thrashed out in the full glare of the public and political arena, across the span of several parliamentary hearings and many written parliamentary questions and answers. Only after a gruelling period of intense political scrutiny was the controversy allowed to subside. 

In the end, there was no evidence to suggest the Attorney had fallen foul of the Shawcross principles in relaying his and other Ministers’ opinions on the prosecution to the Director. Indeed, there was no evidence to suggest that the Attorney would have fallen foul of the principles even if he had issued a direction to discontinue the prosecution, as there was nothing to suggest the Attorney had bowed to political pressure in reaching his own conclusion on where the public interest lay. Rather, he formed his own view about whether a prosecution should proceed based on his assessment of the seriousness of the national security risk and what he took to be the low likelihood of success at trial, a conclusion he stated was backed by independent legal advice. 

But as a responsible minister bound by a constitutional convention, it was incumbent upon the Attorney to robustly defend his position, and its compatibility with fundamental constitutional principle, before the bar of Parliament. It is worth lingering on the significance of what this episode says about the Attorney General’s powers. The episode, and many others detailed in the works of leading scholars like Edwards, neatly encapsulates the power and vitality of a constitutional convention like the Shawcross principles, how seriously they are taken in our parliamentary and political culture, and how the exercise of the Attorney General’s discretionary powers is disciplined by reference to them. 

The Attorney General’s powers are not currently subject to judicial review, but there is scant evidence to suggest this has made them more liable to abuse. What has prevented successive Attorneys General from abusing their extensive powers has been the “strength of character, personal integrity and depth of commitment to the principles of independence” that are demanded of the office and the powerful political imperatives that mandate compliance with the constitution. Whatever the arguments in favour of subjecting the Attorney’s powers to judicial review, it is not a well-founded argument to say they would be otherwise unbridled. 

Thanks to Dr Robert Craig, Professor Richard Ekins KC (Hon), Sir Stephen Laws KC (Hon), Dr Paul Scott, and Professor Se-shauna Wheatle for helpful comments.

Conor Casey, Senior Lecturer in Public Law & Legal Theory, University of Surrey.

(Suggested citation: C. Casey, ‘The Attorney’s Bridle: The Constitutional Convention Disciplining the Attorney General’s Discretionary Powers’, U.K. Const. L. Blog (20th October 2025) (available at https://ukconstitutionallaw.org/))