Criminal law is the part of law that decides what behaviour is against the rules of society and what punishments apply when someone breaks those rules. It aims to keep people safe, protect property, and make sure those who commit offences are dealt with fairly.

In England and Wales, criminal law mainly comes from two places:

• Acts of Parliament (statute law) – for example, the Theft Act 1968 or the Offences Against the Person Act 1861.

• Case law (common law) – rules made by judges in court decisions, such as the law on murder.

To be guilty of most crimes, two things must be proved:

1. Actus Reus (the guilty act) – the physical part of the crime, such as doing something, failing to act when required, or causing a result.

2. Mens Rea (the guilty mind) – the mental part, showing what the defendant was thinking, such as intention or recklessness.

Both of these usually need to happen at the same time. If the defendant has a legal defence, this can prevent a conviction even when the actus reus and mens rea are present.

The burden of proof is on the prosecution, meaning they must prove the case against the defendant. The standard they must reach is beyond reasonable doubt, a very high level of certainty.

Crimes are grouped by how serious they are:

• Summary offences – minor crimes dealt with in the Magistrates’ Court (e.g. minor assaults).

• Either-way offences – can be heard in either the Magistrates’ Court or the Crown Court, depending on seriousness (e.g. theft).

• Indictable offences – the most serious crimes, always tried in the Crown Court (e.g. murder).