In criminal law, theft (also known as stealing or filching) is the illegal taking of another person's property without that person's freely-given consent. As a term, it is used as shorthand for all major crimes against property, encompassing offences such as burglary, embezzlement, larceny, looting, robbery, mugging, trespassing, shoplifting, intrusion, fraud (theft by deception) and sometimes criminal conversion. In some jurisdictions, theft is considered to be synonymous with larceny; in others, theft has replaced larceny.

Someone who carries out an act of or makes a career of theft is known as a thief.

Elements

The actus reus of theft is usually defined as an unauthorised taking, keeping or using of another's property which must be accompanied by a mens rea of dishonesty and/or the intent to permanently deprive the owner or the person with rightful possession of that property or its use.

For example, if X goes to a restaurant and, by mistake, takes Y's scarf instead of her own, she has physically deprived Y of the use of the property (which is the actus reus) but the mistake prevents X from forming the mens rea (i.e. because she believes that she is the owner, she is not dishonest and does not intend to deprive the "owner" of it) so no crime has been committed at this point. But if she realises the mistake when she gets home and could return the scarf to Y, she will steal the scarf if she dishonestly keeps it. Note that there may be civil liability for the torts of trespass to chattels or conversion in either eventuality.

Theft in English law

In English law, theft was codified into a statutory offence in the Theft Act 1968 which defines it as:

"A person is guilty of theft, if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it". (Section 1)

The five elements of the offence are defined sequentially in the Act:

• Section 2 dishonesty;
• Section 3 "appropriation" which occurs when the defendant wrongfully asserts the rights of ownership over the property. This can be by physical taking, but it will also include many different situations (i.e. a failure to return or omission) in which a person may have lawfully come into possession of the property and then keeps or uses the property in an unauthorised way;
• Section 4 "property" includes all personalty, i.e. land itself cannot be stolen but anything severed from the land (with the exception of wild flowers) can be stolen, as can intangible property such as a chose in action; however it seems that the term does not extend to all intangible property, as information (Oxford v. Moss) and trade secrets (R v. Absolom, The Times, 14th September 1983) have been held not to fall within the Section 4 definition of property.
• Section 5 "belonging to another" requires a distinction to be made between ownership, possession and control:

  ownership is where a person is not legally accountable to anyone else for the use of the property: