3. Defences to trespass to the person

Defences to Trespass to the Person

An act that would normally amount to assault, battery, or false imprisonment may be legally excused if the defendant can establish a recognized defence. Where a lawful justification exists, the defendant escapes civil liability. These defences range from personal consent to lawful statutory authority.

Consent

Volenti non fit injuria: Where a claimant agrees to an act that would otherwise be an assault or battery, consent provides a complete defence. This rule reflects the Latin maxim volenti non fit injuria, which means that no legal wrong is done to a willing person. Consent may be given expressly in words or writing, but it is very often implied from conduct.

Sports and games: Participation in contact sports is a classic example of implied consent. A boxer or wrestler cannot sue an opponent for blows received in the ring, because entering the contest implies consent to the ordinary physical contact of the sport. See Wright v McClelland (1956).

Similarly, football players consent to ordinary tackles and incidental physical contact. However, consent does not cover violence that falls entirely outside the rules of the game or beyond what any player would reasonably expect. An athlete remains liable in tort for delivering a deliberate, off-the-ball blow unconnected with ordinary play, as illustrated in R v Billinghurst.

Medical treatment: Consent also applies in medical and dental care. A patient who agrees to surgery or dental extraction cannot sue for battery or false imprisonment regarding the physical interference or standard confinement required for the procedure. The patient consents to the physical contact and assumes the inherent risk that the treatment might fail, provided the treatment stays within the agreed scope. See Siaka v Sierra Leone Diamond (1972-73).

Vitiated consent: Consent must be genuine and freely given. If the defendant obtains consent through fraud, concealment, or physical coercion, the defence fails completely. For example, if a person agrees to be touched with an ordinary metal bar that the defendant secretly knows is connected to an electric current, that consent is invalid. Likewise, submission under violence or duress is not true legal consent.

Self-Defence and Defence of Others

The test of proportionality: A person may use reasonable physical force to protect themselves, another person, or property against an unlawful attack. The central test is reasonableness: the force used must be strictly proportionate to the danger threatened.

Measured response: Proportionality depends on the weapon and the severity of the threat. If an attacker threatens someone with a deadly weapon, the defender is justified in using comparable force to protect their life. Conversely, a person who is merely punched cannot lawfully respond by pulling out a gun or using lethal force. See Cook v Beal (1697).

The courts have long condemned disproportionate retaliation. In Cockcroft v Smith (1705), Holt CJ famously remarked that hitting a man a little blow with a stick on his shoulder is no justification for drawing a sword to cut off his head. The same requirement for proportionate force was reaffirmed in Lane v Holloway (1968).

Defence versus retaliation: Crucially, self-defence only justifies force used to repel an active or imminent attack. It never justifies retaliation or revenge once the threat has passed. If an assailant slaps someone and turns to walk away, striking the assailant from behind is battery, not self-defence.

Parental and Disciplinary Authority

Parental chastisement: At common law, a parent or guardian may lawfully chastise or temporarily confine a child without committing assault, battery, or false imprisonment. This power exists solely for the child's welfare, education, and moral discipline. The physical correction or detention must always be moderate and reasonable in light of the child's age, physical strength, and understanding.

Moderate physical discipline of a ten-year-old child or sending them to their room for misbehaviour may be lawful. In contrast, it is unlawful to inflict corporal punishment on an infant who cannot understand discipline, to cause actual bodily harm to a child, or to lock up an adult daughter to prevent her from seeing someone her parent dislikes.

Schoolteachers: Schoolteachers historically exercised delegated parental authority at common law. Under modern law and human rights principles, teachers may no longer rely on automatic implied authority. Corporal punishment administered without specific parental consent breaches fundamental human rights standards.

Captains of ships and aircraft: The captain of a ship or an aircraft commander holds common law authority to maintain discipline and safety on board. A captain may use reasonable physical force to restrain any crew member or passenger if there are reasonable grounds to believe such restraint is necessary to protect the vessel or its occupants. See Hook v Cunard Steamship Co Ltd (1953).

Necessity

Preventing greater harm: The defence of necessity applies where the defendant intentionally commits what would otherwise be a tort in order to prevent a much greater and more imminent harm. This defence can operate where the defendant acts to protect the claimant, an innocent third party, or the wider public. See Leigh v Gladstone (1909), where prison authorities justified the force-feeding of a hunger-striking prisoner to save her life.

Inevitable Accident

Definition: An inevitable accident is an event that could not have been prevented by the exercise of ordinary care, caution, and skill. Sir Frederick Pollock defined it as an accident not avoidable by any such precautions as a reasonable person could be expected to take.

The standard required is reasonable foresight, not superhuman precaution. In Fardon v Harcourt-Rivington (1832), Lord Dunedin explained that people must guard against reasonable probabilities, but they are not bound to guard against fantastic possibilities. Where harm occurs purely by accident without negligence, the defendant is not liable in trespass. See Stanley v Powell (1891).

Statutory Authority and Lawful Arrest

Statutory justification: Where an act is authorized by an Act of Parliament, the person carrying it out is immune from tort liability. Thus, lawful arrest and lawful detention provide a complete defence to claims for assault, battery, and false imprisonment. When a defendant raises this defence, the burden of proving that the arrest was lawful rests squarely on the defendant.

Reasonable force in arrest: In Sierra Leone, powers of arrest are governed in detail by the Criminal Procedure Act 1965 (Act No. 32 of 1965). Section 4(2) provides that where an arrest is lawful and the suspect attempts to evade capture, a police officer or private person may use only such force as is reasonably necessary to carry out the arrest, and no more.

Powers under the CPA 1965: The Criminal Procedure Act distinguishes between arrests made by private citizens and those made by the police. Section 11 outlines when a private person may arrest an offender without a warrant, and Section 12 mandates that the arrested person must be handed over to the police as soon as possible. Section 13 sets out the wider powers of a police constable to arrest without a warrant.

Notice and constitutional limits: Under Section 15 of the Criminal Procedure Act, anyone executing an arrest must inform the suspect of the true reason for the arrest, unless the suspect is caught in the actual commission of the crime or caught immediately following an escape from custody. Furthermore, Section 17(1) of the Constitution of Sierra Leone 1991 guarantees personal liberty, confirming that deprivation of liberty is only lawful when strictly authorized under one of the specific exceptions provided by law.