UK Computer Misuse Act 1990

The Act creates the UK's core computer offences: unauthorised access to computer material (section 1), unauthorised access with intent to commit or facilitate further offences (section 2) and unauthorised modification of computer material (section 3). It sets territorial scope and significant links with domestic jurisdiction, rules for inchoate offences, proceedings, search warrants, extradition, application to Scotland and Northern Ireland, and interpretation.

It is the foundation of UK cybercrime law, used against hacking and malware, and is relevant to security testing and incident response.

Use it for UK hacking or unauthorised-access offences, assessing whether security research or access is authorised, or jurisdiction over cross-border computer crime.

Any person committing computer-misuse offences with a significant link to the UK.

IN FORCE, AS AMENDED. The supplied copy is the original 1990 text; later Acts added offences (for example sections 3ZA and 3A) and changed penalties, so check the current revised text. Read the official PDF on this page for the operative text.

Section 1 → section 3 → section 17 (interpretation) → sections 4–5 (jurisdiction).