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What is the Computer Misuse Act?

Introduced in 1990, the Computer Misuse Act makes it illegal to acquire access a computer without permission, and make changes to files on a computer without permission. The law was partly introduced in response to the R v Gold & Schifreen (1988) case, whereby they used conventional home computers and modems in 1984 and 1985 to gain access to British Telecom’s Prestel interactive view data service. You can be found guilty of an offence under this legislation if you:

  • Cause a computer to perform any function with intent to secure access to any program or data held in any computer when;
  • Access is unauthorised; and
  • The person knows at the time when they cause the computer to function that is the case.

Amendments to the Computer Misuse Act 1990

The act is still used today, mainly in cases where people are facing accusations of data harvesting, hacking and unauthorised encryption of data. According to the UK's Office for National Statistics (ONS), approximately 4.5 million cybercrimes were committed in England and Wales during 2018, with 1.2 million related directly to computer misuse. There have, however, been a series of amendments over the last three decades, with the most notable in 2015, which made life imprisonment possible in cases where human welfare or national security has been endangered.


Computer Misuse Act offences can be brought before the Magistrates Court or the Crown Court, depending on the severity of the case, however, the different levels of penalties are:

  • Up to two years in prison and a £5,000 fine for gaining unauthorised access to a computer.
  • Up to 10 years in prison and an unlimited fine (depending on the severity of the case) if you acquire unauthorised access to a computer to steal data or use the data to commit fraud.
  • Up to 10 years in prison and an unlimited fine if you modify the content of a computer or provide the tools so that others can alter the content.
  • Up to life imprisonment if the computer misuse puts national security at risk, or causes harm to welfare.

A substantial drop in cybercrimes

With 1.23 million offences related to computer misuse for the year ending March 2018, the ONS reported a 31% drop in cybercrime when compared to 2017. This decrease is a positive step, showing just how important anti-virus technology can be. Successful hacking offences also dropped by 12% to 528,000, suggesting people are more aware of security standards online. That said, even with such positive strides made to reduce cybercrime, there have been cases whereby individuals have been prosecuted for simply doing their job, such as reporters.

If you have been accused of an offence under the Computer Misuse Act or expect an arrest, please get in touch with our highly skilled legal professionals today on 07000 81 82 83 – we’re available 24/7. Alternatively, please email us at and we’ll be in touch with you as soon as possible.

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