A) Consent

• Consent is the most commonly utilised defence to an intentional tort. If the plaintiff gives the defendant consent to trespass a complaint cannot be raised against the defendant. Consent may be given to both trespass to the person and trespass to land and therefore can be used as defence for:
  • assault;
  • battery;
  • false imprisonment;
  • trespass to land; and
  • interference with chattels.
• An example might be a patient who gives a doctor consent to perform an invasive medical procedure or a rugby player who is injured in a tackle made with reasonable force in the context of the game.
• In order to prove this defence you must prove that the consent:
  • was either express or implied;
  • was real and freely given without any duress;
  • and that the person giving consent had legal capacity to give consent.

B) Necessity

• Necessity is a defence that is available where the defendant is unable to obtain consent from the plaintiff but takes action anyway on the basis that it was necessary to do so.
• To successfully establish the defence of necessity the defendant must prove that their actions were:
  • necessary to prevent imminent harm to the plaintiff or their property; and
  • reasonable in the circumstances and proportionate to the risk presented.
• In the medical context necessity may be raised as a defence if:
  • the patient is unconscious; or
  • the patient does not have capacity to consent to the carrying out of immediate lifesaving treatment; and
  • no legally authorised representative is available to give consent on behalf of the patient.