Accessorial liability

Accessorial liability is the law by which a person who does not personally complete the conduct element of an offence may nevertheless be convicted of that offence because he has assisted or encouraged its commission by another. It is not a separate inchoate offence, though it sits beside the Serious Crime Act 2007 offences considered in Week 14. It is a mode of attribution: if D2 is an accessory to D1's burglary, murder, rape, fraud or criminal damage, D2 is convicted of that substantive offence and punished as a principal offender.

The central distinction is between the principal, who perpetrates the actus reus of the offence, and the accessory, who aids, abets, counsels or procures the principal's offence. The vocabulary is old, but the modern doctrinal question is sharp. What did D2 do to assist or encourage? What did D2 know or intend about D1's conduct and fault? What offence, precisely, did D1 commit? The questions are simple in outline and notoriously unstable in application.

For a Cambridge Part IA answer, the essential organising proposition is this: accessorial liability requires both a conduct contribution and a culpable mental relation to the principal offence. After R v Jogee [2016] UKSC 8, foresight that D1 might commit the offence is evidence from which intention may be inferred, but it is not itself the mens rea of accessorial liability. The accessory must intend to assist or encourage the principal in acts which constitute the crime, with knowledge of the essential matters that make those acts criminal. This correction matters especially in homicide and group violence, where the former doctrine of parasitic accessory liability had allowed conviction for murder on the basis that D2 foresaw that D1 might intentionally inflict really serious injury.

The topic is difficult because it crosses several lines drawn earlier in the paper. It forces renewed attention to causation, omissions, mens rea, intoxication, conditional intention, mistake, joint enterprise and inchoate liability. It also exposes a conceptual tension. Criminal law ordinarily insists on personal responsibility: D is liable for D's own conduct and fault. Accessorial liability seems to punish D for another's act. The orthodox answer is that D is punished for participating in the other's offence, but this answer requires discipline. Mere presence is not enough; passive acquiescence is not enough; friendship, association or prior criminality is not enough. Conversely, a very small assistance may suffice if given with the required mental element.

In Tripos terms, this topic is examined both as doctrine and as moral architecture. Problem questions usually involve a group enterprise that changes direction, a weapon not anticipated by all participants, a driver or supplier remote from the scene, or a principal whose own liability is uncertain. Essays usually ask whether Jogee restored orthodoxy, whether complicity is derivative, or whether the law still over-criminalises marginal participants. A strong answer begins with the statute, states the post-Jogee test, separates conduct and mens rea, and then returns to the normative question: what justifies treating D2 as guilty of D1's offence rather than of a lesser participatory wrong?

The common law of parties to crime developed from medieval distinctions between principals in the first degree, principals in the second degree, accessories before the fact and accessories after the fact. Those distinctions mattered procedurally. An accessory before the fact could not ordinarily be tried unless the principal had been convicted; presence at the scene distinguished the principal in the second degree from the absent procurer; and accessories after the fact were treated separately because their conduct followed the offence rather than contributed to it. Modern law has largely abandoned those procedural distinctions, but their language survives in the statutory formula aid, abet, counsel or procure.

The Accessories and Abettors Act 1861, s 8, is the principal statutory foundation for indictable offences. It does not define accessorial liability. It provides the consequence of being a secondary party: the aider, abettor, counsellor or procurer is liable to be tried, indicted and punished as a principal offender. The operative concepts are therefore common law concepts, developed through cases. This is why the topic remains judge-made despite its statutory label.

For much of the twentieth century the cases treated complicity in relatively familiar settings: supplying equipment for a bank robbery, driving the getaway car, encouraging an assault, or procuring an offence by another. Decisions such as Bainbridge and Clarkson drew lines between assistance, encouragement and mere presence. Attorney General's Reference (No 1 of 1975) and Cogan and Leak showed that procuring may operate even where the principal is innocent or lacks mens rea. National Coal Board v Gamble established that an accessory need not desire the principal offence; deliberate assistance with knowledge of the relevant facts is enough.

The largest historical distortion concerned joint enterprise. The phrase was used in several senses. In one sense it merely described parties acting together in committing an offence: two burglars entering a house, or one holding the victim while the other stabs. In another sense it described liability for a collateral offence committed by one participant in the course of a shared venture. The latter sense became known as parasitic accessory liability. Its canonical Privy Council formulation in Chan Wing-Siu v The Queen [1985] AC 168 held that where D2 participated in crime A and foresaw that D1 might commit crime B with the requisite mens rea, D2 could be liable for crime B if D1 committed it. This rule was extended and applied for three decades, especially in homicide cases involving gangs and weapons.

The conceptual problem was that foresight of possibility replaced intention to assist or encourage. The accessory to murder could be convicted although he neither intended that D1 should kill nor intended to assist the use of lethal violence; it was enough that he realised D1 might act with murderous intent. Critics, including Andrew Ashworth, Jeremy Horder, John Gardner and others, argued that the doctrine diluted mens rea and threatened the principle of correspondence between culpability and conviction. Defenders emphasised public protection, group criminality and the moral significance of deliberately joining a dangerous criminal venture.

R v Jogee marked the decisive correction. The Supreme Court and Privy Council held that the common law had taken a wrong turn. Foresight is not mens rea; it is evidence. The accessory's liability must be based on intentional assistance or encouragement, coupled with knowledge of essential facts. Jogee did not abolish secondary liability. It restored its ordinary structure. Nor did it guarantee acquittal in group cases. A jury may infer intention from D2's knowledge of a weapon, words of encouragement, prior planning, continued participation and the nature of the enterprise. But the inference must be made, not bypassed.

This historical movement is examinable because it reveals the law's competing pressures: procedural simplification, public anxiety about group violence, doctrinal fidelity to individual guilt, and the difficulty of proving internal states in collective conduct. A first-class supervision essay should not treat Jogee as a mere technical change. It is an episode in the recurring struggle between preventive criminalisation and the principle that conviction for the principal offence should rest on culpable participation in that offence.

The starting point is analytical separation. First identify the principal offence. Has D1 committed burglary, murder, theft, rape, fraud, criminal damage or another offence? Secondly ask whether D2 contributed by assistance or encouragement. Thirdly ask whether D2 had the required mental element. A common error is to start with group narrative rather than offence structure. Accessorial liability is not liability for being there, being associated with offenders, or behaving badly in the vicinity of crime.

The principal offence. Secondary liability is usually derivative in the sense that there must be a principal offence to which D2 is party. If D1 commits no offence, D2 cannot generally be an accessory to that offence, though D2 may be liable for an inchoate offence under the Serious Crime Act 2007 or conspiracy. There are complications where the immediate actor is innocent, deceived or lacks mens rea. In such cases D may be a principal through innocent agency, or may procure the commission of the actus reus in circumstances where the statutory language permits liability. Cogan and Leak is the standard illustration: Leak induced Cogan to have intercourse with Leak's wife by falsely representing her consent. The court treated Leak's liability as possible notwithstanding the issue over Cogan's own mens rea. The deeper lesson is that one must ask whether D1 is truly the principal offender, an innocent agent, or the instrument through which D commits the crime.

The conduct element. The statutory verbs are aid, abet, counsel and procure. Aid means assist. Abet means encourage, instigate or incite at the time of the offence. Counsel means encourage or advise beforehand. Procure has a stronger causal flavour: D must bring about the principal offence. The labels overlap and do not usually matter if the jury are properly directed on assistance or encouragement. However, procure is sometimes distinctive, because it requires causal contribution. In Attorney General's Reference (No 1 of 1975), spiking another's drink so that he drove over the limit could amount to procuring the offence.

Assistance need not be a but-for cause of the completed offence. Giving a weapon, lending a car, keeping watch, disabling an alarm, providing information or being ready to intervene may amount to assistance even if D1 could have committed the offence without it. The law does not require proof that the crime would not have occurred without D2. It does require real participation rather than coincidence. Encouragement may be express or implied, by words, gestures, prior agreement or conduct at the scene. Presence may be evidence of encouragement, especially where presence gives confidence to D1 or intimidates the victim, but presence alone is insufficient. Clarkson remains the warning: watching and approving internally is not enough unless communicated as encouragement or forming part of assistance.

The landmark cases are best understood as answering five recurring questions: what counts as participation, what mental element is required, how far liability extends where the common plan changes, what happens where the immediate actor is not fully culpable, and how the law should treat group violence.

National Coal Board v Gamble is the orthodox starting point for mens rea before the joint enterprise detour. A weighbridge operator knowingly supplied coal to lorries that were being overloaded. Devlin J held that an accessory need not want the principal offence to occur. If D deliberately does an act of assistance knowing the relevant circumstances, liability may arise. This is crucial for reluctant or commercially motivated assistants. Desire is not necessary; intentional assistance is.

Bainbridge illustrates knowledge of the type of offence. D supplied cutting equipment later used in a bank robbery. He knew the equipment was to be used for breaking into premises, though not necessarily which premises or the precise robbery. The Court of Criminal Appeal held that knowledge need not extend to every detail, but must extend to the essential matters or type of offence. The case remains useful, though after Jogee one should express the point in terms of intentional assistance with knowledge of essential facts.

Clarkson draws the line between presence and encouragement. Soldiers entered a room where a sexual assault was taking place and watched. The court quashed convictions because mere presence, even with secret approval, was insufficient unless it in fact encouraged the principals and D intended encouragement. In problem questions, Clarkson prevents moral disgust from substituting for doctrine. Presence may be evidence, but not an automatic actus reus.

Attorney General's Reference (No 1 of 1975) is the standard procurement case. D secretly laced P's drink with alcohol; P then drove with excess alcohol. The court held that procure means to produce by endeavour and requires a causal link. It is enough that D's act caused the offence to be committed, though P need not know of D's involvement. This is particularly important for offences of strict liability or offences where the principal may be unaware of the circumstance produced by D.

Cogan and Leak is conceptually awkward but pedagogically important. Leak encouraged Cogan to have intercourse with Leak's wife by representing that she consented. Cogan was acquitted; Leak's conviction was upheld on the basis that he procured the act. The case is often discussed under innocent agency and derivative liability. Its safest use in an exam is to show that the law can sometimes reach the manipulator even where the immediate actor's liability is problematic, but one should avoid treating it as a general abolition of derivativeness.

Bryce concerns remote assistance and purpose. D arranged a meeting between the principal and another person, knowing that the principal intended murder. The Court of Appeal treated assistance as capable of existing even though D was not present at the killing and his contribution was preparatory. The case shows that remoteness is not fatal where assistance is intentional and connected to the offence.

Gnango is unusual and should be handled cautiously. Two gunmen fired at each other in a public place; one shot killed an innocent passer-by. The Supreme Court upheld Gnango's conviction for murder on the basis of joint participation in an affray or mutual gunfight and accessorial principles. The reasoning is controversial and fact-specific. Its main value is to demonstrate the elasticity of participation analysis, not to supply a general rule that victims of attacks are accessories to their own murder.

Jogee is the modern centre. The Supreme Court held that the law had wrongly equated foresight with mens rea in parasitic accessory liability. The proper question is whether D2 intentionally assisted or encouraged D1 to commit the crime, with the necessary knowledge of essential facts. Foresight that D1 might commit the offence is evidence from which intention may be inferred. It is not itself the mental element. Every contemporary problem answer must apply Jogee rather than the older Chan Wing-Siu rule.

See practice questions section below.

See further reading section below.