📚 Year 12 WJEC Law: Key Principles & Formulas Quick Reference | WJEC 法律学年12：核心原理与规则速查手册
In WJEC Year 12 Law, understanding legal liability often comes down to mastering a set of logical 'formulas' and structured rules. This quick-reference handbook distils the essential principles of criminal law, tort law, and contract law into clear equations and checklists, helping you apply the law to scenario questions with precision.
在 WJEC 法律学年12 课程中，理解法律责任往往可以归结为掌握一组逻辑“公式”和结构化的规则。这本速查手册将刑法、侵权法和合同法的基本原理提炼成清晰的方程式和核查清单，帮助你精准地将法律应用于案例情景题。
1. The Criminal Liability Equation | 刑事责任方程式
In English criminal law, a defendant is liable if the prosecution proves they committed the actus reus of an offence with the required mens rea, and no complete defence applies.
在英格兰刑法中，若控方能证明被告人以所要求的犯罪意图实施了某罪行的犯罪行为，且不存在完整辩护理由，则被告人须承担刑事责任。
The basic formula is: Actus Reus + Mens Rea – Defence = Criminal Liability.
基本公式为：犯罪行为 + 犯罪意图 - 辩护 = 刑事责任。
Actus reus refers to the 'guilty act'. It can be a voluntary act, an omission (where a legal duty to act exists, e.g., contractual duty, familial duty, or assumed responsibility), or a state of affairs.
犯罪行为指“有罪行为”。它可以是自愿作为、不作为（若存在法律上的作为义务，例如合同义务、亲属义务或自愿承担的责任）或状态。
Mens rea is the 'guilty mind'. The main types are intention (direct or oblique – see R v Woollin), recklessness (Cunningham subjective: the defendant foresaw the risk and went on to take it), and negligence (objective failure to meet a standard).
犯罪意图是“有罪心理”。主要类型包括故意（直接或间接——见R v Woollin案）、轻率（Cunningham主观标准：被告人预见了风险但仍冒险行事）和过失（客观未达到应有标准）。
If a defence such as self-defence, duress, or insanity is successfully raised, the equation negatives liability.
若成功提出诸如自卫、被迫或精神错乱等辩护，则该方程式可使责任不成立。
2. Strict Liability: Liability Without Mens Rea | 严格责任：无犯意之责任
is needed for at least one element of the actus reus. The formula is: Actus Reus = Guilty.
严格责任罪行只要求证明犯罪行为；犯罪行为的至少一个要素无需证明犯罪意图。其公式为：犯罪行为 = 有罪。
These are usually regulatory or quasi-criminal offences, such as selling alcohol to a minor, or food safety violations. The presumption of mens rea can be displaced by the words of the statute (Gammon test).
这类罪行通常属于监管性或准刑事犯罪，例如向未成年人售酒或违反食品安全规定。犯罪意图的推定可因法条用词而被推翻（Gammon检验标准）。
The defence of due diligence or a third party's act may be available if expressly provided by statute.
若法规明确规定，可以提出尽职调查或第三人行为等辩护理由。
3. Non-Fatal Offences Hierarchy | 非致命罪行层级
The non-fatal offences against the person form a ladder of seriousness. Understanding their actus reus and mens rea formulas is vital for problem solving.
针对人身的非致命罪行构成一个严重性阶梯。理解其犯罪行为与犯罪意图公式对解决问题至关重要。
| Offence 罪行 | Actus Reus 犯罪行为 | Mens Rea 犯罪意图 | Max Sentence 最高刑罚 |
|---|---|---|---|
| Assault 普通威胁 | Causing victim to apprehend immediate unlawful force 使被害人担心会遭受立即非法武力 | Intention or recklessness as to causing such apprehension 故意或轻率地引起该担心 | 6 months / fine 6个月 / 罚金 |
| Battery 普通殴打 | Application of unlawful force 施加非法武力 | Intention or recklessness as to applying unlawful force 故意或轻率地施加非法武力 | 6 months / fine |
| s.47 ABH 实际身体伤害 | Assault or battery causing actual bodily harm 威胁或殴打造成实际身体伤害 | Intention or recklessness as to the assault/battery (no need to intend harm) 对威胁/殴打的故意或轻率(无需意图造成伤害) | 5 years 5年 |
| s.20 GBH 恶意重伤 | Wounding or inflicting grievous bodily harm 创伤或造成严重身体伤害 | Malice: intention or recklessness as to some harm (foresight of some harm suffices) 恶意：故意或轻率地造成某种伤害(预见某种伤害即可) | 5 years |
| s.18 GBH with intent 意图重伤 | Wounding or causing GBH 创伤或造成严重身体伤害 | Specific intent to cause GBH or to resist/prevent lawful arrest 故意造成严重身体伤害或抗拒/阻止合法逮捕的特定意图 | Life 终身监禁 |
Note that for s.47, only the mens rea of the base assault/battery is required, not mens rea for the harm actually caused (Roberts).
注意，对于s.47，仅需要基础威胁或殴打的犯罪意图，而无需对所造成伤害的犯罪意图（Roberts案）。
4. The Negligence Equation | 过失侵权方程式
elements. The formula is: Duty of Care + Breach of Duty + Causation + Damage = Negligence.
要确立过失侵权责任，原告必须证明四个要素。其公式为：谨慎义务 + 违反义务 + 因果关系 + 损害 = 过失责任。
All four elements must be present. If any one is missing, the claim fails.
四个要素必须全部具备。若缺少任何一个，索赔即不成立。
'Damage' must be a recognised type of loss, such as personal injury, property damage, or in limited circumstances pure economic loss or psychiatric harm.
“损害”必须是法律承认的损失类型，例如人身伤害、财产损害，或在有限情形下的纯粹经济损失或精神损害。
5. Duty of Care: The Caparo Test | 谨慎义务：Caparo三阶检验
The modern test for establishing a novel duty of care comes from Caparo Industries v Dickman. The formula requires three stages:
确立新型谨慎义务的现代检验标准源自Caparo Industries v Dickman案。该公式要求三个阶段：
(1) Foreseeability of harm – was it reasonably foreseeable that the defendant's conduct could cause damage to a person in the claimant's position?
(1) 损害的可预见性——被告的行为是否合理地可预见会对处于原告境况的人造成损害？
(2) Proximity – was there a sufficiently close relationship between the claimant and defendant (legal proximity, not just physical)?
(2) 相近性——原告与被告之间是否存在足够密切的关系（法律上的相近性，而不仅是物理邻近）？
(3) Fair, just and reasonable – would it be fair, just and reasonable to impose a duty?
(3) 公平、公正与合理——施加义务是否公平、公正且合理？
In cases falling within established duty situations (e.g., driver to road users, manufacturer to consumer per Donoghue v Stevenson), the Caparo test need not be applied; it is primarily for novel situations.
若案件属于已有的义务情形（例如驾驶员对道路使用者、制造商对消费者的义务，见Donoghue v Stevenson案），则无需适用Caparo检验；该检验主要用于新型情形。
Robinson v Chief Constable of West Yorkshire confirms that where precedent exists, courts should follow it rather than reinvent the duty analysis.
Robinson v Chief Constable of West Yorkshire案确认，在已有先例时，法院应遵循先例，而非重新进行义务分析。
6. Breach of Duty: The Reasonable Man | 违反义务：合理人标准
Breach is determined by asking whether the defendant fell below the standard of the reasonable person. The test is objective, not subjective.
判断是否违反义务，是看被告是否低于合理人的注意标准。该检验是客观的，而非主观的。
The following factors are weighed to set the standard:
设定标准时需权衡以下因素：
- Likelihood of harm (Bolton v Stone): if the risk is very low, the standard adjusts.
- 损害发生的可能性（Bolton v Stone案）：若风险极低，标准可相应调整。
- Magnitude of potential harm (Paris v Stepney): greater potential harm demands higher precautions.
- 潜在损害的严重程度（Paris v Stepney案）：潜在损害越大，要求的防范措施越高。
- Cost and practicality of precautions (Latimer v AEC): a reasonable person is not required to take disproportionate steps.
- 防范措施的成本及现实可行性（Latimer v AEC案）：不要求合理人采取不成比例的防范措施。
- Social utility of the activity (Watt v Hertfordshire): if the defendant's activity has high social value, a higher risk may be tolerated.
- 活动的社会效益（Watt v Hertfordshire案）：若被告行为具有高社会价值，可容许较高的风险。
For professional defendants, the Bolam test applies: a professional is not negligent if they acted in accordance with a practice accepted as proper by a responsible body of professional opinion.
对于专业被告，适用Bolam检验标准：若专业人士的行为符合当时被同行专家群体认可为恰当的惯例，则不构成过失。
7. Causation in Tort | 侵权法中的因果关系
Causation has two limbs: factual causation and legal causation. The claimant must prove both on the balance of probabilities.
因果关系包含两个层面：事实因果关系与法律因果关系。原告必须依盖然性权衡标准证明两者均成立。
Factual causation uses the 'but for' test: but for the defendant's breach, would the claimant have suffered the damage? (Barnett v Chelsea). If the damage would have occurred anyway, causation fails.
事实因果关系采用“若非”检验：若非被告的违反义务行为，原告是否会遭受该损害？（Barnett v Chelsea案）。若无论有无违反，损害均会发生，则因果关系不成立。
Legal causation requires that the defendant's breach was a more than minimal cause of the damage (a cause that was not de minimis). The defendant need not be the sole cause.
法律因果关系要求被告的违反义务行为是造成损害的超过最低限度的原因（非微不足道的原因）。被告不必是唯一原因。
A novus actus interveniens – a new intervening act – may break the chain of causation if it is unforeseeable or a free, deliberate act of a third party.
若发生新的介入行为——不可预见的、或第三人自愿故意的行为——可中断因果链条。
The thin skull rule: the defendant must take the victim as found. If the claimant has a pre-existing vulnerability that makes the harm more severe, the defendant is still liable for the full extent (Smith v Leech Brain).
薄头骨规则：被告必须接受被害人既有的状况。若原告因原有脆弱特质而使伤害更严重，被告仍须对全部损害负责（Smith v Leech Brain案）。
8. Contract Formation Formula | 合同成立公式
xist: Offer + Acceptance + Consideration + Intention to Create Legal Relations = Contract.
当以下要素同时存在时，一个有约束力的合同即告成立：要约 + 承诺 + 对价 + 建立法律关系的意图 = 合同。
An offer is a statement of willingness to contract on specific terms, made with the intention that it will become binding upon acceptance (Gibson v Manchester City Council).
要约是对按特定条款订约的意愿声明，并带有一旦被承诺即受约束的意图（Gibson v Manchester City Council案）。
An invitation to treat is not an offer; it is an invitation for others to make offers. Examples include goods on display (Fisher v Bell; Pharmaceutical Society of GB v Boots Cash Chemists) and advertisements (Partridge v Crittenden).
要约邀请不是要约，而是邀请他人发出要约。示例包括陈列商品（Fisher v Bell案；Pharmaceutical Society of GB v Boots Cash Chemists案）和广告（Partridge v Crittenden案）。
Acceptance must be a mirror image of the offer and communicated to the offeror. The postal rule (Adams v Lindsell) is an exception: acceptance by post takes effect when the letter is posted, provided it was reasonable to use the post.
承诺必须与要约完全一致，并传达给要约人。邮寄规则（Adams v Lindsell案）是例外：以邮寄方式承诺的，在信件投入邮筒时即生效，前提是使用邮寄方式是合理的。
9. Consideration Rules | 对价规则
Consideration is the price paid for the promise. The classic definition is from Currie v Misa: 'some right, interest, profit or benefit accruing to one party, or some forbearance, detriment, loss or responsibility undertaken by the other.'
对价是为承诺支付的对价。经典定义来自Currie v Misa案：“一方取得某种权利、利益、利润或好处，或另一方承受某种克制、损害、损失或责任。”
The key rules of consideration are:
对价的关键规则如下：
- Consideration must be sufficient but need not be adequate: the court does not assess whether the price was fair (Thomas v Thomas).
- 对价必须充分，但无须等价：法院不评估价格是否公平（Thomas v Thomas案）。
- Past consideration is no consideration: the act must be done in response to the promise, not before (Re McArdle).
- 过去的对价不构成对价：行为必须因应允诺而作出，而非在此之前（Re McArdle案）。
- Performance of an existing public duty, or an existing contractual duty owed to a third party, can amount to consideration (Ward v Byham; Scotson v Pegg). However, performance of an existing contractual duty owed to the promisor generally is not good consideration unless there is a practical benefit (Williams v Roffey).
- 履行既有的公共义务、或对第三人承担的既有合同义务，可构成对价（Ward v Byham案；Scotson v Pegg案）。然而，履行对允诺人本已负有的既有合同义务，一般不构成有效对价，除非存在实际利益（Williams v Roffey案）。
- Part payment of a debt is not consideration for a promise to forgo the balance (Pinnel's Case), unless there is some additional element or the promissory estoppel applies (High Trees).
- 部分还款不构成对免除余款承诺的对价（Pinnel案），除非存在额外因素，或允诺禁反言规则适用（High Trees案）。
10. Intention to Create Legal Relations | 建立法律关系的意图
For a contract to exist, the parties must intend to be legally bound. The courts apply two presumptions:
合同要成立，双方当事人必须具备受法律约束的意图。法院适用两项推定：
- Social and domestic agreements: presumed not to be legally binding (Balfour v Balfour; Jones v Padavatton). This can be rebutted by clear evidence of contrary intention (Merritt v Merritt).
- 社交及家庭协议：推定为不具有法律约束力（Balfour v Balfour案；Jones v Padavatton案）。若有明确相反意图的证据，可予推翻（Merritt v Merritt案）。
- Commercial agreements: strongly presumed to be legally binding (Edwards v Skyways). Rebuttal requires very strong evidence (Rose & Frank Co v Crompton).
- 商业协议：强烈推定为具有法律约束力（Edwards v Skyways案）。推翻该推定须有极其有力的证据（Rose & Frank Co v Crompton案）。
11. Defences in Crime: Key Formulas | 刑事辩护关键公式
tablished, a complete defence may exonerate the defendant. The formula then reads: AR + MR – Complete Defence = No Liability.
即便犯罪行为与犯罪意图均已成立，完整辩护仍可免除被告人的责任。此时方程式为：犯罪行为 + 犯罪意图 - 完整辩护 = 无需承担责任。
Self-defence / prevention of crime (common law & s.76 Criminal Justice and Immigration Act 2008): the defendant must genuinely believe force was necessary, and the force used must be reasonable in the circumstances as the defendant perceived them (R v Owino; R v Palmer).
自卫/防止犯罪（普通法及2008年《刑事司法与移民法》第76条）：被告人必须真正相信使用武力是必要的，且在其所认知的情形下使用的武力必须是合理的（R v Owino案；R v Palmer案）。
Insanity (M'Naghten rules): the defendant must prove, on the balance of probabilities, that at the time of the act they were suffering from a defect of reason, from a disease of the mind, so as not to know the nature and quality of the act, or that what they were doing was wrong.
精神错乱（M'Naghten规则）：被告人须以盖然性权衡标准证明，其在行为当时因精神疾病导致理性缺陷，从而不知行为性质和实质，或不知所做之事是错误的。
Intoxication: voluntary intoxication is no defence to basic intent crimes (DPP v Majewski), but may negate the specific intent for specific intent crimes. Involuntary intoxication may provide a defence if the defendant lacked the mens rea.
醉酒：自愿醉酒不构成对基本意图罪行的辩护（DPP v Majewski案），但对于特定意图罪行，可因缺乏特定意图而否定犯罪意图。非自愿醉酒若导致被告人欠缺犯罪意图，可构成辩护。
Consent: for non-fatal offences, consent can be a defence to assault and battery, but not to actual bodily harm or more serious harm unless within recognised exceptions (e.g., surgery, sports, tattooing) (R v Brown).
同意：对非致命罪行，同意可作为普通威胁和殴打的辩护，但对实际身体伤害或更严重伤害，除非落入公认的例外情形（如手术、体育竞技、纹身），否则不能作为辩护（R v Brown案）。
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