How Can the Courts Prove Intention to Commit a Crime?

When a defendant is charged with a criminal offence, the prosecution must prove that the defendant both committed the act (‘actus reus’), and had the required mental element of intent (‘mens rea’). The mental element is that the defendant intended or foresaw the natural consequences of the actus reus.

Inferring intention

According to section 8 of the Criminal Justice Act 1967, “a court or jury, in determining whether a person has committed an offence… shall decide whether he did intend or foresee that result by reference to all the evidence, drawing such inferences from the evidence as appear proper in the circumstances”. However, a person can act intentionally or recklessly.

The distinction between acting with intention and acting recklessly

A person may act with the intention to commit a crime. For example, if they set out with a weapon determined to physically hurt their neighbour, they would have the intention of carrying out an offence against the person.

If a person acts recklessly as to the consequences, they have a choice to take an unjustified risk that the result may occur. For example, if a person sets fire to a pile of newspapers with the intention of burning only the newspaper, but the newspapers were next to a wheelie bin, they would be acting recklessly as they were reckless as to the risk that the wheelie bin may catch fire.


A person may not intend the consequences of his action, but can act recklessly and still be convicted. Recklessness in this context is the taking of an unjustified risk. The type of recklessness that is required to prove guilt may be objective (the reasonable man test), or subjective (was the risk in the defendant’s mind at the time) depending on the offence in question.

The distinction between direct intention and oblique intention

The common law classifies intention as either direct or oblique intention. There is direct intention where the defendant acted criminally with the direct intention to bring about a result. In other words, the consequence/s were the defendant’s specific purpose or intention.

Oblique intention is where a person acts with the intention that the circumstances of their actions are virtually certain to occur.

Direct Intention

It may not always be clear whether the defendant intended or foresaw the consequences of their actions. Proving intention can be just as difficult. Where intention is an issue, the prosecution will consider the aim and the purpose of the defendant’s intention. There has been a long-established test that helps the criminal courts establish direct intention – Duff’s ‘Rule of Thumb’.

Duffs Rule of Thumb is a test that consists of success/failure reasoning. The prosecution will ask if a person would regard themselves as having failed if the result that did occur had not happened.Essentially, if the action does not produce an expected effect, will it have been a failure? If yes – it was intended. If not, it was at most foreseen. Furthermore, it is quite possible that the consequences were neither intended nor foreseen. This will be a question of fact for the jury (or magistrates) to decide on the evidence.

Oblique intention

The jury will be directed to find the defendant as having oblique intention if itis satisfied beyond reasonable doubt that the defendant knew the result was a virtual certainty, and chose to act in the way they did regardless.

About the Author

Nicola Laver LLB

Nicola is a dual qualified journalist and non-practising solicitor. She is a legal journalist, editor and author with more than 20 years' experience writing about the law.

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