The Computer Misuse Act 1990 (CMA) is a UK law that was introduced in 1990 to address the issue of computer-related crime. The law is designed to protect computer users and systems from unauthorised access, hacking, and other forms of cybercrime.
In this article, we will explore the Computer Misuse Act in more detail, including its key provisions, penalties for breaking the law, and notable cases where the act has been enforced.
Key Provisions of the Computer Misuse Act
The Computer Misuse Act contains three main sections that outline offenses related to unauthorised access, unauthorised modification of computer material, and unauthorised access with intent to commit or facilitate a crime.
Section 1: Unauthorized access to computer material
Section 1 of the CMA makes it an offense to gain unauthorised access to any computer material. This includes accessing data or systems without permission, as well as using any unauthorised method to gain access to a computer.
Section 2: Unauthorized access with intent to commit or facilitate a crime
Section 2 of the CMA makes it an offense to gain unauthorised access to a computer with the intention of committing or facilitating a crime. This could include stealing data, distributing viruses or malware, or using a computer to commit fraud.
Section 3: Unauthorized modification of computer material
Section 3 of the CMA makes it an offense to modify or destroy computer material without authorization. This could include deleting files, changing data, or introducing malware.
Penalties for Breaking the Law
The penalties for breaking the Computer Misuse Act vary depending on the severity of the offense. For less serious offenses, the maximum penalty is a fine or up to two years in prison.
For more serious offenses, such as those involving significant financial loss or damage, the maximum penalty is ten years in prison.
Notable Cases
Over the years, there have been several notable cases where the Computer Misuse Act has been enforced. In 2018, a teenager was sentenced to two years in prison for his role in the Mirai botnet attack. The attack, which used hundreds of thousands of compromised Internet of Things devices, caused significant disruption to websites and services around the world.
In 2015, a man was sentenced to two years in prison for hacking into the US Department of Defense’s computer system. The man, who was based in the UK, used a technique called “SQL injection” to gain unauthorised access to the system.
Summary
The Computer Misuse Act is an important law that helps to protect computer users and systems from cybercrime. The act contains several provisions that make it illegal to gain unauthorized access to computer systems or data, modify computer material without authorization, or use a computer to commit a crime.
Penalties for breaking the law range from fines to prison sentences, depending on the severity of the offense.
The Computer Misuse Act has been used in several high-profile cases over the years, highlighting the importance of strong laws to combat cybercrime.
The Ministry of Injustice was attacked on the 14th March 2023 from outside of the UK and the jurisdiction of the Computer Misuse Act 1990. Better luck next time.
The gov.uk website has various help and guidance on Crime, justice and the law.






The Ministry of Injustice is not the Ministry of Justice nor is it affiliated in any way with the justice system, legal profession or any law enforcement agencies.
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Computer Misuse Act 1990 was last updated on the 8th July 2025