Definition of Offence

1. What is a Criminal Offence?

A criminal offence is a breach of a rule recognised by the state as so serious that the state itself prosecutes the offender on behalf of the public. This section introduces the two building blocks of every offence — the actus reus and the mens rea — and surveys the four overlapping sources of criminal law in England and Wales.

Criminal proceedings are brought in the name of the Crown (R v Defendant), the prosecution bears the legal burden of proof, and the standard of proof is beyond reasonable doubt: Woolmington v DPP [1935] AC 462. A successful prosecution results in conviction and sentence — typically a fine, community order, suspended sentence or custody under the Sentencing Act 2020.

Every criminal offence is made up of two elements. The external, physical element is the actus reus (AR): the conduct, circumstances and consequences that the defendant must cause or be in. The internal, mental element is the mens rea (MR): the state of mind the defendant must have at the time the actus reus occurs. With very few exceptions (strict liability offences), the prosecution must prove both. The actus reus and the mens rea must in principle coincide in time — a rule discussed at 1.3.5 below.

1.1.1 Sources of Criminal Law in England and Wales

Criminal law derives from four overlapping sources. Candidates often assume that every offence is codified in an Act of Parliament, but that is not the case.

2. Actus Reus

The actus reus of an offence is not simply the defendant's 'guilty act'. The label is misleading because an actus reus can be made up of acts, omissions, circumstances, consequences or a combination of them. The reliable way to identify the actus reus is to write out the statutory (or common law) definition of the offence, strike out every reference to the defendant's state of mind, and treat what is left as the actus reus.

Take the example of theft under s. 1(1) Theft Act 1968: 'A person is guilty of theft if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it.' Stripped of the mental elements ('dishonestly', 'with the intention of permanently depriving'), the actus reus is the appropriation of property belonging to another. Every element of that actus reus must be proved by the prosecution.

1.2.1 Conduct, Result and State-of-Affairs Crimes

It is useful to classify offences by the type of actus reus they require, because this tells you what the prosecution has to prove and where causation becomes relevant.

Conduct crimes are committed as soon as the defendant performs the prohibited act. Perjury is a classic example — the offence is complete when the false statement is made on oath, whether or not it influences the outcome of the trial. Most inchoate offences (including attempt under s. 1 Criminal Attempts Act 1981, Chapter 10) are conduct crimes.

Result crimes require the defendant's act to produce a particular consequence. Murder requires the victim's death; wounding or causing GBH under s. 18 OAPA 1861 requires a wound or GBH; criminal damage under s. 1(1) Criminal Damage Act 1971 requires damage or destruction. For result crimes the prosecution must also prove causation (1.2.3 below).

State-of-affairs crimes do not require the defendant to act at all; the actus reus is simply being in a certain situation. Winzar v Chief Constable of Kent (1983) The Times, 28 March — a defendant who had been brought onto a public highway by police was held to have committed the offence of being found drunk in a public place — is the usual illustration. These offences demonstrate that voluntariness is not an absolute requirement.

1.2.2 Omissions

The starting point is the general rule that English criminal law does not punish pure omissions: there is no general duty to rescue a stranger or to prevent harm. The classic illustration is that a person who walks past a child drowning in a shallow pool and does nothing commits no offence, however morally reprehensible their inaction. The general rule is subject, however, to an important set of exceptions in which the defendant has assumed or been placed under a duty to act, and the omission will found liability for the same offence as a positive act would have done.

1.2.3 Causation

Causation is relevant only to result crimes. Where the offence requires a consequence, the prosecution must prove that the defendant's conduct caused the consequence both in fact and in law. The two limbs are cumulative: failure at either stage defeats the charge.

1.2.3.1 Factual Causation — the 'but for' test

The factual causation test asks: would the result have occurred but for the defendant's act? If the answer is yes (it would have happened anyway), factual causation is not made out and the defendant is not the cause of the result, however morally blameworthy he may be. The classic illustration is R v White [1910] 2 KB 124, where the defendant put cyanide in his mother's drink but she died of an unrelated heart attack before the poison took effect. The mother would have died anyway; the defendant was not the factual cause of her death and could be convicted only of attempted murder.

1.2.3.2 Legal Causation — the 'substantial and operating' test

Legal causation asks whether the defendant's act was a substantial and operating cause of the result. The act must be a more than minimal cause (R v Hughes [2013] UKSC 56; R v Pagett (1983) 76 Cr App R 279). It need not be the only cause, nor even the main cause, but it must contribute significantly to the result.

The chain of causation must not be broken by a novus actus interveniens — an intervening act that is so unexpected, free and independent of the defendant's act that it renders the original act no longer operative.

1.2.3.3 Intervening Acts that Break the Chain

Three categories of intervening event may break the chain of causation.

3. Mens Rea

The mental element required varies from offence to offence. There are five families of mens rea in the FLK2 syllabus: intention (direct and oblique), recklessness, knowledge and belief, dishonesty, and — for a small number of offences — negligence. Strict liability offences, which require no mens rea at all as to one or more elements of the actus reus, are rare and almost always regulatory in nature.

1.3.1 Intention — Direct and Oblique

Intention is the highest form of mens rea. Direct intention is aim or purpose: the defendant acts in order to bring about the result. A defendant who fires a gun at the victim's head, wanting the victim dead, directly intends death — whether or not the victim is far away, whether or not the shot is likely to succeed, and regardless of motive (R v Moloney [1985] AC 905).

A defendant may also be found to have intended a result that he did not specifically want, provided the result was a virtually certain consequence of his action and he foresaw it as such. This is oblique (or indirect) intention. The modern formulation comes from R v Woollin [1999] 1 AC 82: the jury is not entitled to find intention unless they feel sure that the result was a virtual certainty barring some unforeseen intervention, and that the defendant appreciated that to be the case. Even when the Woollin test is satisfied, oblique intention is a matter of inference — the jury is entitled, but not obliged, to find intention (R v Matthews & Alleyne [2003] EWCA Crim 192).

1.3.2 Recklessness — the R v G Subjective Test

Since R v G [2003] UKHL 50, the test for recklessness in English criminal law is subjective: the defendant is reckless if, at the material time, he was aware of a risk that a particular result would follow or that particular circumstances existed, and in the circumstances known to him it was unreasonable for him to take that risk. This overturned the objective test previously applied in Metropolitan Police Commissioner v Caldwell [1982] AC 341, under which a defendant could be reckless if a reasonable person would have seen the risk even though the defendant himself did not.

The G test has two limbs that must both be satisfied. First, the defendant must actually have appreciated the risk — it is not enough that he would have, or should have. Second, the risk he took must have been an unreasonable one in the circumstances known to him. Taking an obvious risk with no justification is unreasonable; taking a small risk to achieve a socially valuable objective (for example, a surgeon operating to save a patient's life) is not.

1.3.3 Negligence and Gross Negligence

Negligence is not generally a form of mens rea in criminal law, because it does not require any awareness on the defendant's part: it is simply a failure to meet the standard of care that a reasonable person would have met. A few offences are, however, defined in terms of negligence. Careless driving under s. 3 Road Traffic Act 1988 is the obvious example; rape under s. 1 Sexual Offences Act 2003 also has a negligence element ('does not reasonably believe that B consents').

Gross negligence is the form of mens rea required for gross negligence manslaughter (Chapter 3). It is much more than ordinary negligence: the defendant's conduct must, in the view of the jury, be so bad in all the circumstances as to amount to a criminal act or omission (R v Adomako [1995] 1 AC 171). The full six-stage test restated in R v Broughton [2020] EWCA Crim 1093 is dealt with in Chapter 3.

1.3.4 Transferred Malice

Where a defendant has the mens rea for an offence against a particular victim but, through misaim or mistake, the actus reus of the same offence is committed against a different victim, the law transfers the defendant's mens rea to the actual victim. The doctrine was established in R v Latimer (1886) 17 QBD 359: the defendant swung his belt at a man in a pub, but the belt bounced off and struck a woman nearby, wounding her. He was held to have the mens rea for the wounding offence against her because the mens rea was 'transferred' from the intended victim.

1.3.5 Coincidence of Actus Reus and Mens Rea

As a general rule the prosecution must prove that the actus reus and the mens rea coincided in time: the defendant must have had the required mens rea at the moment he committed the actus reus. Two doctrines soften the rule where a strict temporal requirement would produce an absurd result.

Together, these two doctrines ensure that a defendant cannot escape liability simply because there is a short gap, or a mistaken belief, between the moment the mens rea is formed and the moment the actus reus is completed.

4. The SQE1 FLK2 Assessment & How to Use This Book

Criminal Law and Practice is tested in FLK2, which also covers Dispute Resolution, Contract Law (including equitable remedies), Tort, the Legal System of England and Wales, Constitutional Law, EU Law and Human Rights. This section explains how the topic is examined and how this book is structured.

The assessment consists of two 180-minute papers on consecutive days, each with 180 single best answer questions. Between 10% and 18% of the total FLK2 questions are on Criminal Law and Practice.

Every question is a single best answer scenario. You will be given a short factual scenario, usually written from the perspective of a solicitor advising a client, and then asked: 'Which ONE of the following statements is correct?' or 'What is the best advice to the client?'. There are five options (A–E) and only one is correct. There is no negative marking, so you should always answer every question.

This book covers every topic in the SRA's FLK2 specification for Criminal Law and Practice. The 27 chapters are grouped into six units: Unit 1 (Chapters 1–6) — principles of criminal liability and substantive offences; Unit 2 (Chapters 7–10) — defences, parties and inchoate liability; Unit 3 (Chapters 11–14) — the police station; Unit 4 (Chapters 15–19) — pre-trial procedure; Unit 5 (Chapters 20–23) — evidence; and Unit 6 (Chapters 24–27) — trial, sentencing, appeals and the youth court.

Each chapter follows the same structure: an SQE assessment advice box, the substantive content with Key Term and Exam Tip callouts, and three consolidation features — a Key Notes summary table, five focused Revision Notes in Q&A form, and five SQE1-style single best answer questions with fully-explained answer keys. Give yourself 1 minute 40 seconds per question and do not look at the answer key until you have chosen an option. Case names appear in italics throughout, and statute references use the SRA form (e.g. 's. 47 OAPA 1861').

5. Key Notes (Chapter Summary)

The following summary table consolidates every term, rule and authority examined in this chapter. Treat it as a revision checklist — you should be able to state each row from memory together with its leading case.

6. Revision Notes (Q&A)

Work through each of the five focused revision prompts below. Attempt each one from memory first — the note underneath gives the model answer and explains why the point matters for FLK2.

Q1. Difference between actus reus and mens rea; the general rule about proof; and why mens rea alone cannot convict

Note. Every offence has two elements: the actus reus (the external, physical element — conduct, circumstances, and for result crimes the prohibited consequence) and the mens rea (the internal, mental element — intention, recklessness, knowledge, belief, dishonesty or negligence, depending on the offence). The prosecution must prove both elements beyond reasonable doubt (Woolmington v DPP [1935] AC 462). A defendant cannot be convicted on mens rea alone because criminal law punishes conduct, not thoughts: an evil wish without any external act is not a crime, however obvious the intent — a plan to kill recorded in a diary but never acted on cannot support a murder charge. The converse (that actus reus alone suffices) is also false, except for the narrow category of strict liability offences in which Parliament has dispensed with mens rea for one or more elements (Sweet v Parsley [1970] AC 132; Gammon (Hong Kong) v AG [1985] AC 1). In FLK2 this most often comes up as a distractor: a defendant plainly intends a crime but has done nothing, and the tempting (wrong) answer is to convict — the correct answer is that the actus reus must also be proved.

Q2. The general rule about omissions and the principal duty-based exceptions

Note. The general rule is that English criminal law does not punish pure omissions — there is no general legal duty to rescue a stranger, and a person may watch a child drown in a shallow pool without committing any offence. The rule is displaced only where the defendant owes a positive duty to act. The principal duty-based exceptions are: (i) statutory duty (e.g. duty to provide a specimen of breath under s. 6 Road Traffic Act 1988); (ii) contractual duty — R v Pittwood (1902), the railway gatekeeper; (iii) special relationship (parent/child, spouse/spouse, carer/dependant) — R v Gibbins & Proctor (1918), R v Stone & Dobinson [1977]; (iv) voluntary assumption of responsibility — R v Evans [2009] EWCA Crim 650 (half-sister overdosed on supplied heroin, defendant failed to summon help); (v) creation of a dangerous situation — R v Miller [1983] 2 AC 161 (smouldering mattress); and (vi) holding public office — R v Dytham [1979] QB 722 (police officer who watched a fatal attack). Where a category applies, the omission is treated as if it were a positive act and the defendant can be convicted of the same offence — including manslaughter or even murder. FLK2 MCQs test the six categories directly: if none applies, the correct answer is that no offence was committed.

Q3. The two limbs of causation in result crimes and when an intervening event breaks the chain

Note. The defendant's act must be both the factual and the legal cause of the prohibited result. Factual causation is the 'but for' question: but for the defendant's act, would the result have occurred in the way and at the time it did? If yes, the defendant is not the factual cause — R v White [1910] 2 KB 124 (poison not yet taken effect when the victim died of an independent heart attack). Legal causation asks whether the act was a 'substantial and operating' cause — more than minimal, though not necessarily the only or main cause (R v Hughes [2013] UKSC 56; R v Pagett (1983) 76 Cr App R 279). The chain may be broken by a novus actus interveniens in three ways: (a) an act of the victim breaks the chain only if 'so daft' as to be unforeseeable (R v Roberts (1971)); a free, voluntary and informed self-injection of supplied drugs does break it (R v Kennedy (No 2) [2007] UKHL 38); (b) an act of a third party breaks the chain only if so independent as to render the original wound merely part of the history — bad medical treatment ordinarily does not (R v Smith [1959]; R v Cheshire [1991]), the exception being R v Jordan (1956) ('palpably wrong'); (c) an extraordinary, unforeseeable natural event may break the chain (ordinary natural events do not). Finally, the thin-skull rule means the defendant must take the victim as he finds him — R v Blaue [1975] 1 WLR 1411 (Jehovah's Witness refusing a transfusion). Recognise Smith/Cheshire as the rule and Jordan as the exception.

Q4. Direct v oblique intention; the Woollin test; why the jury is not obliged to find intention even when Woollin is satisfied

Note. Direct intention is the defendant's aim or purpose: he acts in order to bring about the result — a defendant who fires at the victim's head wanting death has direct intention whether or not the shot is likely to succeed; motive (e.g. mercy killing) is irrelevant. Oblique intention arises where the defendant does not aim at the result but acts knowing it is a virtually certain consequence. The modern formulation, R v Woollin [1999] 1 AC 82, is that the jury is not entitled to find intention unless (i) they feel sure the result was a virtual certainty (barring some unforeseen intervention), and (ii) the defendant appreciated this was so. The test is cumulative. Even where both limbs are met, the finding of intention is an inference the jury is entitled, but not obliged, to draw — explicit in R v Matthews & Alleyne [2003] EWCA Crim 192. The reason is that Woollin is a rule of evidence, not a rule of substantive law: virtual certainty is evidence from which intention may be inferred, not a conclusive definition. In FLK2 murder MCQs the Woollin scenario is typically a defendant who places a bomb on a plane for insurance money, or who throws a child from a bridge — work the two-limb test and, if satisfied, the jury may find intent to kill or cause GBH.

Q5. The rule on coincidence of actus reus and mens rea and the two softening doctrines

Note. The general rule is that the defendant must have the required mens rea at the moment he commits the actus reus. If the mens rea is formed after the actus reus is complete, or has dissipated before it is committed, the rule is not satisfied. Two judicially-created doctrines soften the rule. (i) The continuing act doctrine: where the actus reus is a continuing act, it is enough that the defendant formed the mens rea at some point while the act was still going on — Fagan v Metropolitan Police Commissioner [1969] 1 QB 439 (defendant accidentally drove onto a police officer's foot, was asked to move, and refused; driving onto and remaining on the foot was a single continuing act and the mens rea for battery was formed while it continued). (ii) The single transaction doctrine: where the conduct is a series of acts forming a single indivisible transaction, the law treats the whole series as one actus reus and it is sufficient that the defendant had the mens rea at some point during it — Thabo Meli v R [1954] 1 WLR 228 (defendants beat the victim intending to kill, believed him dead, rolled him over a cliff; death was caused by exposure, not the beating — held a single transaction, mens rea at the time of the beating sufficient for murder). See also R v Church [1966] 1 QB 59 (applied to manslaughter). Coincidence is rarely a standalone topic but is a useful analytical tool where a scenario looks like it might fail on timing.

7. MCQ Practice — Five SQE-Style Questions

Test your understanding with the following five SQE1-style single best answer questions. Each has five options (A–E) and only one is correct. Give yourself one minute and forty seconds per question and answer each question before turning to the answer key. The answer key explains why each option is correct or incorrect — read every explanation in full.

A. The chain of causation is broken because the cleaner's negligence was the immediate cause of death.

B. The chain of causation is broken because the neighbour would have recovered from the wound but for the cleaner's act.

C. The chain of causation is not broken because the original stab wound remained a substantial and operating cause of death.

D. The chain of causation is not broken only because the cleaner's negligence was foreseeable.

E. The chain of causation is broken because medical negligence always breaks the chain of causation in homicide cases.

A. The client is not liable because there is no general duty to rescue a stranger.

B. The client is not liable because he did not cause the chest infection.

C. The client is liable because he voluntarily assumed responsibility for the victim's welfare.

D. The client is liable because homelessness creates a special relationship with any person who offers help.

E. The client is liable because his failure to act created a dangerous situation.

A. The man had direct intention to kill because the result of his conduct was death.

B. The man had no mens rea for murder because his purpose was insurance fraud, not killing.

C. The man is guilty of murder only if the prosecution can prove that death was a probable result of his conduct.

D. The jury is entitled, but not obliged, to find intention to kill or cause GBH if they are sure that death or serious injury was a virtual certainty and the man appreciated that this was so.

E. Recklessness as to death is sufficient mens rea for murder, so the jury may convict on that basis.

A. The defendant is not liable in respect of the nephew because the mens rea was directed at a different person.

B. The defendant's mens rea is transferred to the nephew under the doctrine of transferred malice because wounding the brother-in-law and wounding the nephew are offences of the same kind.

C. The defendant's mens rea can only be transferred if the nephew's injury was foreseen.

D. Transferred malice does not apply under s. 20 OAPA 1861 because the offence requires specific intent.

E. Transferred malice only applies where the defendant had the intent to kill.

A. The motorist is not liable because the mens rea was formed only after the application of force was complete.

B. The motorist is liable because the act of keeping the wheel on the officer's foot was a continuing act and the mens rea was formed while the act was still going on.

C. The motorist is liable because the officer's foot was a thin-skull victim.

D. The motorist is liable because battery is a strict liability offence and mens rea is not required.

E. The motorist is not liable because there was no positive act — the car was stationary when the mens rea was formed.