All Acts
Cyber· 1990

CMA 1990

Computer Misuse Act 1990

Principal cybercrime statute — criminalises unauthorised access, unauthorised access with intent, unauthorised modification, and supplying tools for use in offences.

Self-test

Sections

Section 1 — Unauthorised access to computer material

Causing a computer to perform any function with intent to secure unauthorised access to any program or data, knowing the access is unauthorised.

Key points
  • Either-way — max 2 years on indictment.
  • Includes guessing/sharing passwords, snooping on a colleague's account, basic hacking.

Section 2 — Unauthorised access with intent to commit further offence

Section 1 offence committed with intent to commit (or facilitate) a further indictable offence (e.g., fraud, blackmail).

Key points
  • Either-way — max 5 years on indictment.

Section 3 — Unauthorised acts impairing operation of computer

Doing any unauthorised act in relation to a computer with intent or recklessness as to impairing operation, preventing/hindering access to data, or impairing reliability/operation of programs/data.

Key points
  • Either-way — max 10 years on indictment.
  • Covers DDoS attacks, deploying malware, ransomware, wiping data.

Section 3ZA — Unauthorised acts causing or creating risk of serious damage

Unauthorised act in relation to a computer causing, or creating a significant risk of, serious damage to human welfare, the environment, the economy, or national security.

Key points
  • Indictable only — up to LIFE imprisonment where damage to human welfare/national security.
  • Targets attacks on CNI — power grids, water, NHS systems, transport networks.