Core principles of criminal liability - Parties to an offenc...

Learning Outcomes

This article explains the law on parties to criminal offences in England and Wales, including:

• The distinction between principal offenders, joint principals, secondary parties (accessories), and innocent agents, and how each contributes to the commission of an offence
• The statutory foundations of accessorial liability, focusing on the categories of aiding, abetting, counselling, and procuring and their respective legal effects
• The required actus reus and mens rea for secondary liability, including knowledge of essential matters, intention and conditional intent to assist or encourage, and the derivative nature of accessory liability
• The modern approach to joint enterprise following R v Jogee, contrasting it with the former parasitic accessory liability model and clarifying the role of foresight and conditional intent
• Problem areas such as mere presence, association, withdrawal, and situations where the principal acts outside the original plan, and how these differ from inchoate liability (e.g. attempts and Serious Crime Act 2007 offences)
• The practical and ethical implications when advising and representing clients, including explaining potential principal and accessory liability clearly and complying with professional conduct obligations

SQE2 Syllabus

For SQE2, you are required to demonstrate detailed knowledge and precise application of the law regarding parties to criminal offences, with a focus on the following syllabus points:

• The definitions and distinctions between principal offenders, joint principals, secondary parties (accessories), and innocent agents.
• The four statutory types of secondary party conduct that may incur accessory liability: aid, abet, counsel, and procure.
• The required actus reus for secondary liability (assistance or encouragement before or during the commission of the principal offence).
• The required mens rea for secondary liability, including knowledge of essential matters and intention to assist or encourage (including conditional intent for joint enterprise).
• The legal basis and current scope of joint enterprise liability following R v Jogee [2016] UKSC 8, including changes in the law and the doctrine of conditional intent.
• The concept and application of "innocent agent" situations as distinct from secondary liability.
• The doctrine of derivation in accessory liability: the accessory's liability is dependent on (but not identical to) the principal's commission of the actus reus, and not on the principal's conviction.
• The boundaries between accessorial and inchoate offences (e.g., attempts, encouraging or assisting).
• The law and practical operation of withdrawal for secondary parties, including the requirements for effective withdrawal in planned and spontaneous offences.
• Recognition and analysis of issues such as mere presence, association, uncertainty as to party status, and liability where the principal acts outside the agreed plan.
• Advising clients accurately and ethically regarding their liability and the application of the law in practical, scenario-based contexts.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. Name the four statutory types of secondary party conduct that may incur accessory liability.
2. True or false? An accessory can be convicted even if the principal offender is acquitted, so long as the actus reus of the offence is established.
3. What is the current mens rea test for secondary liability following the Supreme Court’s decision in R v Jogee?
4. In an exam scenario, what key facts would indicate that a mere bystander might be criminally liable as an accessory?

Introduction

Criminal liability is not limited to those who actually perform the criminal act; the law recognises a wider scope, holding liable those who deliberately assist or encourage the commission of an offence. These distinctions underpin the way criminal responsibility is attributed where two or more parties interact in the commission of crime. An accurate understanding of these principles is essential both for advising clients and for successfully analysing problem scenarios in legal practice.

Key Term: principal offender
The person who commits the conduct element (actus reus) of the offence, coupled with the requisite fault element (mens rea). The principal may act alone or be one of multiple principal offenders.

Key Term: secondary party (accessory)
A person who aids, abets, counsels, or procures the commission of the offence by the principal, but does not execute the actus reus of the principal offence directly.

Key Term: joint principal
Where two or more persons share the essential conduct and intention of the offence and so are each liable as principals. Each joint principal must perform or participate in the actus reus and have the necessary mens rea.

Key Term: innocent agent
An individual who commits the actus reus of the principal offence but lacks capacity or mens rea, or otherwise acts without knowledge of the offence, typically as a tool of another (the true principal).

The law also makes provision for the liability of those who purposely involve or instruct someone who lacks capacity or mental element to commit a crime—termed "innocent agent" liability. In such cases, the directing party is deemed the principal.

Classification of parties to an offence

Criminal law classifies offenders according to their roles in the offence:

• Principal offenders: Commit the offence by personally performing the actus reus with the necessary mens rea.
• Joint principals: Where two or more individuals participate together in performing the actus reus with the requisite mens rea, e.g. both strike the fatal blow in murder, or both enter and steal during a burglary.
• Secondary parties (accomplices or accessories): Aid, abet, counsel, or procure the commission of the offence. They do not themselves carry out the actus reus, but render intentional assistance or encouragement.
• Innocent agents: Commit the physical act at the direction or instigation of another, but cannot be liable themselves; liability attaches to the directing party.

It is important to distinguish between a secondary party and a principal acting via an innocent agent: in the former, the principal knows what he is doing, with mens rea, whereas in the latter, the agent lacks the mens rea or is legally incapable of liability for the offence.

Key Term: conditional intent (joint enterprise)
A form of intention under which the secondary party intends to assist or encourage a principal in the commission of crime A, and, in the specific context of joint enterprise, also intends to assist or encourage a further offence (crime B) should it occur in the course of the planned venture.

Secondary liability: aid, abet, counsel, procure

Accessory liability is primarily governed by section 8 of the Accessories and Abettors Act 1861, which makes it an offence to "aid, abet, counsel, or procure" the commission of indicatable and either-way offences. Section 44 of the Magistrates' Courts Act 1980 extends this to summary-only offences.

Key Term: aid
To assist, support, or help the principal to commit the offence.

Key Term: abet
To incite, induce, or encourage the principal to commit the offence.

Key Term: counsel
To advise, solicit, or urge the principal to commit the offence, typically by persuasion or guidance.

Key Term: procure
To bring about or cause the commission of the offence, usually by direct causation, whether or not the principal is aware of the procurement.

The terms overlap, but each represents an independently sufficient basis for liability. For aid, abet, or counsel, the accessory's contribution need not cause the principal's act—communication is sufficient if it reaches and is received by the principal. For procurement, causation is required: the act of procurement must result in the principal committing the offence.

These forms of participation may occur before or during the commission of the offence, but not after its completion—the latter is instead a matter for offences such as assisting an offender.

Requirements for secondary liability

There are two core elements:

• Actus reus: The secondary party must provide assistance (aid), encouragement (abet, counsel), or direct causation (procure) before or during the commission of the offence. Passive conduct may be enough if, given the circumstances, it is interpreted by the principal as encouragement, such as presence supporting a crime by approval. However, presence is only sufficient when intended and understood as supportive.

• Mens rea: The secondary party must intend to assist or encourage the principal in the commission of the offence, and must have knowledge (or at least an awareness) of the essential facts which make the act criminal, including the type of offence and relevant circumstances. Mere foresight is not sufficient, but may be powerful evidence of intent when the facts suggest conditional intent (see below).

Key Term: actus reus (secondary liability)
Assistance or encouragement by words, actions, or omission where a duty exists, which must relate to the commission of a specific crime. The assistance or encouragement must reach or be intended for the attention of the principal.

Key Term: mens rea (secondary liability)
An intention to assist or encourage the principal’s criminal conduct, with knowledge of essential facts that make the act criminal (type of offence, participants, key circumstances). The secondary party must both intend to aid, abet, counsel, or procure, and intend that the principal act with the required mens rea for the principal offence.

Knowledge of essential matters

The accessory must know, or believe with sufficient certainty, the essential facts that constitute the principal offence. This does not mean knowledge of the exact time, place, or all details, but that the accessory is aware of the type of crime (e.g., burglary, not just some crime or illegality) and, where a range of possible crimes is contemplated, liability attaches where the principal commits an offence within that range.

It is not enough that the accessory merely suspects some wrongdoing or is indifferent; the law requires knowledge (or conditional intention: the intent to assist or encourage the commission of an offence, including within a contemplated range).

Intention to assist or encourage

Intention is established where the secondary party acts deliberately to support the commission of the offence by the principal, either as a direct aim or as a conditional intent. Foresight of the possibility that an offence might be committed is merely evidence, but not itself proof, of intention. However, where the evidence shows that the accessory intended to lend assistance or encouragement should the principal choose to commit a more serious or different crime, conditional intent is sufficient to establish liability.

Mere presence and encouragement

Mere presence at the scene of a crime does not, by itself, make someone a secondary party. However, presence, coupled with conduct or circumstances showing active support, can suffice if intended and understood as encouragement (for example, by joining a group that confronts a victim, standing by as backup, or acting as lookout).

The courts expect participation: an active step, word (such as urging, approval, or acting as lookout), or deliberate presence to evidence support or readiness to act. Where facts show that presence amounts to encouragement, that, together with intention, is sufficient for liability.

Withdrawal

A secondary party who changes their mind can avoid liability by withdrawing from the enterprise. Effective withdrawal requires both timely and unambiguous communication of withdrawal (by words or conduct) before the commission of the offence. The more active a role played or the closer to commission of the offence, the more is required to withdraw (e.g., seeking to neutralise previous encouragement, taking reasonable steps to prevent the offence, or, if present, physically intervening).

Key Term: withdrawal (secondary party)
Effective withdrawal is demonstrated by clear communication of withdrawal to the principal, together with any reasonable steps necessary in the circumstances to cancel or counter prior assistance or encouragement, to the extent possible before the principal commits the crime.

Joint enterprise (parasitic accessory liability)

Joint enterprise is a doctrine whereby two or more parties pursue a shared plan or common purpose, and each can be liable for offences falling within that plan. As clarified by R v Jogee [2016] UKSC 8, it is no longer sufficient for a party merely to foresee that another may commit a further offence (parasitic accessory liability). Instead, liability depends on whether the secondary party intended to assist or encourage the principal to commit that particular offence, including through conditional intention.

If, in the course of carrying out their shared plan (such as a robbery), one participant commits an additional offence (e.g., murder or GBH), the other will only be liable for that additional offence if the evidence shows he intended, at the relevant time, to assist or encourage its commission, even if only conditionally (i.e., prepared to give assistance if it occurred).

Key Term: joint enterprise
Where two or more parties act with a shared intention to commit a crime, each is liable for acts that fall within that shared intention and which he/she intended to assist or encourage.

Conditional intent (joint enterprise)

The law accepts that parties may intend, as part of a joint venture, to provide assistance or encouragement not only to the planned crime (A), but also, conditionally, to further offences (B) if they occur in the execution of the plan.

Worked Example 1.1

Scenario: Laura and Pete plan to rob a shop together. Pete enters the shop and steals the money. Laura waits outside in the car and drives him away.

Answer:
Laura is an accessory (secondary party). She aids Pete by acting as the getaway driver, which is assistance before or during the commission of the robbery. If she intended to assist Pete and knew he was robbing the shop, she is criminally liable as an accessory to robbery.

Worked Example 1.2

Scenario: Ravi attends a brawl but does not participate. He stands with his arms folded, watching silently, after arriving with the main attackers.

Answer:
Possibly. If the prosecution can prove, beyond being merely present, that Ravi’s presence encouraged the attackers (for example, he arrived with them, stood close by, did not object, or was available to assist), this could amount to abetting. The court would also require evidence that Ravi intended his presence to be encouragement.

Worked Example 1.3

Scenario: Anya buys petrol for Mark, knowing he will use it to commit arson. She believes his intention is only to burn an abandoned shed, not a house with people inside. Mark sets fire to an occupied house and people are injured.

Answer:
Anya will only be liable for the aggravated (endangering life) arson if she intended assistance for such an offence and knew that the facts would potentially endanger life. If her knowledge or intention was limited to simple arson, her liability is restricted accordingly. The prosecution would have to show Anya's conditional intent to assist arson that endangered life for her to be liable for that aggravated offence.

Worked Example 1.4

Scenario: Ben provides a gun to Alex, intending only to scare a victim. Ben loads the gun with blanks. However, Alex is unaware the gun was loaded with live ammunition and shoots the victim, causing death.

Answer:
Ben, as the supplier of the weapon and knowing the potential, is likely to be liable as an accessory to murder if he intended that Alex would use it to kill. However, if Ben only intended to help frighten the victim and did not contemplate the use of lethal force, Ben may not be liable for murder (he could be liable for a lesser offence based on his knowledge and intention at the time of assistance). Alex, in this case, lacked the intention for murder if he believed the gun only contained blanks, but Ben's greater intent would dictate his own liability.

Worked Example 1.5

Scenario: Sarah stands watch while her friends break into a house, not caring which of a number of houses on the street is targeted. She knows a burglary will occur but not which property.

Answer:
Knowledge of the type of crime (burglary) is sufficient. Sarah does not need precise details of the date, time, or victim. As long as she intends to provide assistance for a burglary and the principal(s) commit that offence, Sarah is an accessory.

Exam Warning

For SQE2, scrutinise both the evidence of active assistance/encouragement and the intention to assist or encourage the particular crime, not just some crime or general illegality. Foresight alone of a further or more serious offence is not enough; there must be conditional intent demonstrated by the evidence (see Jogee and post-Jogee case law).

Practicalities: application and conduct issues

• Uncertainty as to party status: Where evidence suggests a person may have been a principal or a secondary party but the prosecution cannot prove which, a conviction is possible if satisfied of involvement in at least one legal role (principal or accessory). The jury will be directed to consider both routes to liability.
• Mere association and passive presence: Friendship, association, or mere awareness of criminal intent does not create liability. There must be evidence of active and voluntary assistance or encouragement, or of presence intended as encouragement.
• Distinction from inchoate liability: Secondary liability requires the actual commission of the principal's actus reus; inchoate offences (e.g., attempt, encouraging/assisting under Serious Crime Act 2007) do not. An individual who withdraws before the principal offence is committed may still be liable for an inchoate offence.
• Transference of mens rea: The accessory is liable for their own mens rea and the actus reus of assistance or encouragement, not simply for involvement in a group or for being present.

Inchoate offences distinguished

It is essential to distinguish accessorial liability, which depends on a completed principal offence, from inchoate liability, which attaches to conduct that goes beyond mere preparation but does not result in the completed offence. For example, attempts and the statutory offences of encouraging or assisting under ss 44–46 of the Serious Crime Act 2007 can be charged even if the principal offence does not occur.

Key Point Checklist

This article has covered the following key knowledge points:

• The principal offender is the party whose conduct and intention satisfies the actus reus and mens rea of the criminal offence.
• Secondary parties (accessories) may be liable by aiding, abetting, counselling, or procuring the principal’s offence, subject to correct actus reus and mens rea elements.
• Both direct and indirect (via an innocent agent) involvement in the actus reus can attract criminal liability as a principal.
• Joint principal liability arises where two or more act together to fulfil the actus reus and have the requisite mental element.
• Liability for joint enterprise requires actual intention (not mere foresight) to assist or encourage the commission of that offence, as clarified by the Supreme Court in R v Jogee.
• Accessorial liability is derivative of the principal's commission of the actus reus, but does not require the principal's conviction; the accessory may be liable even where the principal is acquitted for reasons personal to them.
• Knowledge of the essential matters (including the type of crime) is required for secondary liability, but not necessarily specific details such as timing or location.
• Conditional intent enables secondary liability where the evidence shows the accessory intended to assist a further offence if it arose in the execution of the plan.
• Mere presence at the scene is generally not enough for liability, but, if intended as support or encouragement and understood as such, may amount to abetting.
• Withdrawal can absolve an accessory from liability, requiring unequivocal communication and, where reasonable, neutralisation of prior assistance or encouragement before the offence is committed.
• Secondary liability is distinct from inchoate liability (such as attempt or encouragement/assistance under the Serious Crime Act), as the latter does not require the principal’s offence to be completed.
• Where the accessory’s mens rea differs from the principal’s (e.g. intending greater or lesser harm), the accessory may be convicted of a more or less serious offence, depending on their own mental state and intent.
• Professional conduct rules strictly prohibit misleading the court as to the facts or a client’s involvement—a solicitor must act in the client’s best interests but never mislead the court about a client’s liability as principal or accessory.

Key Terms and Concepts

• principal offender
• secondary party (accessory)
• joint principal
• innocent agent
• aid
• abet
• counsel
• procure
• actus reus (secondary liability)
• mens rea (secondary liability)
• conditional intent (joint enterprise)
• withdrawal (secondary party)
• joint enterprise

Key Term: conditional intent (joint enterprise)
Where the accessory intends to assist or encourage the commission of a further offence, should it arise as part of the agreed plan, even if not the principal intention at the outset.

Key Term: innocent agent
An individual who performs the actus reus of the offence without knowledge, capacity, or necessary mens rea, typically manipulated or instructed by a principal who bears liability for the completed act.

This enriched article ensures full syllabus coverage of the law relating to principal and secondary liability, joint enterprise (with reference to conditional intent), the innocent agent doctrine, and the practical and ethical implications for legal professionals. The synthesis here provides detailed explanation and critical detail that enables effective application and advice in criminal practice.