Legal Dictionary


Definition of fault


  • (RP) IPA: /f"ːlt/, /f'lt/, SAMPA: /fO:lt/
  • (US) IPA: /f"lt/, SAMPA: /fOlt/
  • (cot-caught merger) IPA: /fɑlt/
  • Audio (US) [?]
  • Audio (UK) [?]
  • Rhymes: -"ːlt


    From Middle English faulte, faute, from Anglo-Norman faute, faulte, from Old French faute, faulte, from Vulgar Latin *fallita (“shortcoming”), from Latin falsus, perfect passive participle of fallō (“deceive”). Displaced native Middle English schuld, schuild (“fault”) (from Old English scyld (“fault”)), Middle English lac (“fault, lack”) (from Middle Dutch lak (“lack, fault”)), Middle English last (“fault, vice”) (from Old Norse lǫstr, löstr (“fault, vice, crime”)).


fault (plural faults)

  1. A defect; something that detracts from perfection.
  2. A mistake or error.
  3. A weakness of character.
  4. A minor offense.
  5. Blame; the responsibility for a mistake.


fault (third-person singular simple present faults, present participle faulting, simple past and past participle faulted)

  1. (transitive) To criticize, blame or find fault with something or someone.
  2. (intransitive, geology) To fracture.
  3. (intransitive) To commit a mistake or error.

Further reading

Fault, as a legal term, refers to legal blameworthiness and responsibility in each area of law. It refers to both the actus reus and the mental state of the defendant. The basic principle is that a defendant should be able to contemplate the harm that his actions may cause, and therefore should aim to avoid such actions. Different forms of liability employ different notions of fault, in some there is no need to prove fault.

Fault is an essential element in law. For instance, in family law, in order for a divorce petition to succeed the courts have to see some form of fault from one of the parties. In the case of adultery, this act would be committed by one party member (e.g. the man) which would be grounds for the other party (e.g. the woman) to file for divorce. In this case the party accused of adultery would be at fault.

In criminal law, the mens rea is used to decide if the defendant has criminal intent when he commits the act and, if so, he is therefore liable for the crime. However, this is not necessary for strict liability offences, where no state of mind is required.

Actus reus element

Most requirements for a successful Actus Reus require a voluntary act, or omission, for evidence of fault. There is also a requirement for a clear causation, there is no liability or fault if the defendant was not actually the sole cause of the act, this is so if there was an intervention of a third party, an unexpected natural event, or the victims own act. Either of these can remove the legal blame from the defendant and remove the fault.

If the defendant commits a voluntary criminal act, there is strong evidence that he is at fault, and responsible for the crime; However if the act is caused by an involuntary act, such as an act of automatism, or duress the defendant will not be at fault, and therefore not liable.

- Automatism

If the criminal act is caused by an act of automatism, it means the act was caused by an involuntary movement of the limbs, and not controlled by neuron stimulation, removing the blameworthiness from the defendant. This was seen in the case of Hill v Baxter (1958) where the defendant injured a person by crashing his car into them. He argued that his action was not voluntary because he was unaware of what happened. However, he was found guilty because the judge held that sleepiness or drowsiness when driving does not amount to automatism. If, though, he crashed as a result of an extraordinary event (e.g. getting attacked by a swamp of bees), then his actions could be considered automatic.

- Duress

In the case of Duress, the defendant has committed the act in response to a threat of death of serious personal injury to himself or a loved one, or someone he feels responsible towards. Therefore he is removed of fault as his actions were done to prevent such harm being done to himself or a loved one, or to someone he feels responsible towards. It would be considered unfair to place the defendant at fault of a criminal action which he committed under duress.

- Liability

In such cases of a "state of affairs" crimes, the defendant may not be at fault (i.e. purposefully commit a criminal act voluntarily) however they are still liable. This is seen in R v Larsonneur (1933), where the defendant was French and entered the UK, but then got deported to Ireland, and then deported back to the UK, the defendant was not at fault as she did not intentionally re-enter the UK under the Alien Act, however she was still liable for the crime under this act, as there was no need to prove fault. This was also seen in the case of Winzar v Chief Constable of Kent (1983) where the defendant was admitted to hospital by a friend who was worried for his health, however when the hospital realized he was merely drunk to the point of being semi - unconscious, they threw him out of the hospital. The defendant because of his intoxicated state could not get home, and was liable for been drunk and disorderly. Even though he did not have intention for the crime, not was he at fault, due to the crime been one of state of affairs he was liable and charged as such.

- Causation

There is also an issue of causation, in this the courts look at both factual causation (blaue) and legal causation (Paget and white), if both can establish fault, then there is a criminal liability. This is because the defendant will be at fault if he directly caused the act to occur, and did nothing to stop it.

Mens rea element

The mens rea involves the different states of mind which demonstrate the relationship between degree of fault and liability. Depending on the different state of mind of the defendant at the time of committing the unlawful act, different sentences will be given.

- Murder

For a specific intent offence, such as murder, seen in the case of R v Vickers (1957), this requires the defendant to intentionally cause the damage, be fully aware that his actions will lead to the desired consequence of murder. And this is what the defendant intended to occur from his actions. This is the most serious of states of mind the defendant can have, and this high level of fault is reflected in strict and long sentencing, usually life, or on the judge's discretion. However if a murder is done with specific intent in the name of a religion, ideology etc., or on particularly vulnerable groups of people such as children, and continuously (such as terrorism, or a serial child killer) then it may be that the defendant is given a whole life tariff (never sees daylight again).

- Recklessness

There is also subjective recklessness, such as in the case of R v Cunningham (1957), where the defendant is not required to intend the consequence to come from his actions, but the defendant realised the risk that this consequence would occur and took the risk anyway. Such state of mind is required in most non - fatal offences, such as

  • common assault (see section 39 of the Criminal Justice Act 1988)
  • the assault element of assault occasioning actual bodily harm, contrary to section 47 of the Offences against the Person Act 1861
  • inflicting grievous bodily harm, contrary to section 20 of that Act.

In all of these offences the defendant is liable off the offence and at fault if he commits the offence intending for the damage to be done, or being subjectively reckless as to whether the damage occurs. For these reckless is sufficient to prove fault in the defendant.

- Gross negligence

The defendant can also be grossly negligent, which is the mens rea required by involuntary manslaughter offences, such as seen in the case of R v Adomako (1994[, where the defendant was held to be negligent as he had "breached a duty of care".


  1. Wiktionary. Published under the Creative Commons Attribution/Share-Alike License.


1.     lex causae
2.     lex situs
3.     lex loci celebrationis
4.     lex patriae
5.     Clayton's Case
6.     lex domicilii
7.     AORO
8.     lex loci delicti commissi
9.     defence of property
10.     Miranda warning