The ICO exists to empower you through information.

Latest updates

03 October 2023 - this guidance has been updated to include:

  • A new Upper Tribunal decision has been added - DVLA v Williams, Williams v Devon & Cornwall Police
  • Content on the voluntary supply of information has been absorbed into this guidance from a piece of guidance that previously stood alone.
  • Examples of ICO decision notices have been updated.
  • The three “parts” of the exemption are now referred to as “criminal and civil law”; “regulatory powers” and “civil proceedings”.


This guidance discusses section 31 in detail and is written for use by public authorities. Read it if you have questions not answered in the Guide to FOIA, or if you need a deeper understanding to help you apply this exemption in practice.

What does FOIA say?

Section 31 states:

31.—(1) Information which is not exempt information by virtue of section 30 is exempt information if its disclosure under this Act would, or would be likely to, prejudice -

(a) the prevention or detection of crime,

(b) the apprehension or prosecution of offenders,

(c) the administration of justice,

(d) the assessment or collection of any tax or duty or of any imposition of a similar nature,

(e) the operation of immigration controls,

(f) the maintenance of security and good order in prisons or in other institutions where persons are lawfully detained,

(g) the exercise by any public authority of its functions for any of the purposes specified in subsection (2),

(h) any civil proceedings which are brought by or on behalf of a public authority and arise out of an investigation conducted, for any purposes specified in subsection (2), by or on behalf of the authority by virtue of Her Majesty’s prerogative or by virtue of powers conferred by or under an enactment, or

(i) any inquiry held under the Fatal Accidents and Sudden Deaths Inquiries (Scotland) Act 1976 to the extent that the inquiry arises out of an investigation conducted, for any of the purposes specified in subsection (2), by or on behalf of the authority by virtue of Her Majesty’s prerogative or by virtue of powers conferred by or under an enactment.

(2) The purposes referred to in subsection (1)(g) to (i) are -

(a) the purpose of ascertaining whether any person has failed to comply with the law,

(b) the purpose of ascertaining whether any person is responsible for any conduct which is improper,

(c) the purpose of ascertaining whether circumstances which would justify regulatory action in pursuance of any enactment exist or may arise,

(d) the purpose of ascertaining a person’s fitness or competence in relation to the management of bodies corporate or in relation to any profession or other activity which he is, or seeks to become, authorised to carry on,

(e) the purpose of ascertaining the cause of an accident,

(f) the purpose of protecting charities against misconduct or mismanagement (whether by trustees or other persons) in their administration,

(g) the purpose of protecting the property of charities from loss or misapplication,

(h) the purpose of recovering the property of charities,

(i) the purpose of securing the health, safety and welfare of persons at work, and

(j) the purpose of protecting persons other than persons at work against risk to health or safety arising out of or in connection with actions of persons at work.

(3) The duty to confirm or deny does not arise if, or to the extent that, compliance with section 1(1)(a) would, or would be likely to, prejudice any of the matters mentioned in subsection (1).

Section 31 is a prejudice-based exemption. This means that you must demonstrate that disclosing the information could be harmful. It is also subject to a public interest test. The tests you must apply are discussed in more detail below.

In broad terms, the exemption will apply where disclosing information would harm either your ability, or the ability of another body, to enforce the law.

The exemption is split into multiple sub-sections, each covering a different form of harm. You can rely on one sub-section or several sub-sections. However, you must be clear on which sub-section you are relying on and why it applies. You can also rely on this exemption to refuse to confirm or deny whether you hold the information.

You should interpret the term ‘law enforcement’ broadly. In William Thomas Stevenson v the Information Commissioner and North Lancashire Teaching Primary Care Trust [2013] UKUT 0181 (AAC), the Upper Tribunal commented that:

“it is plain from reading the activities listed in s.31(1) and the purposes specified in s.31(2), that they include activities and purposes which go beyond actual law enforcement in the sense of taking civil or criminal or regulatory proceedings. They include a wide variety of activities which can be regarded as in aid of or related to the enforcement of (i) the criminal law, (ii) any regulatory regime established by statute, (iii) professional and other disciplinary codes, (iv) standards of fitness and competence for acting as a company director or other manager of a corporate body (v) aspects of law relating to charities and their property and (vi) standards of health and safety at work” (paragraph 75).