Exemption Index logoFOIMan blags information on the FOI Act’s exemptions designed to keep files that could compromise law enforcement behind bars.


The Kray brothers of FOI exemptions, sections 30 and 31 are the crime lords of the Act’s protection racket. One judge summarised their effect as follows:

“Between them, sections 30 and 31 provide a scheme of exemption, subject to the balance of public interest test, for information held for the purposes of criminal investigation and prosecution and for a range of other investigatory, regulatory and enforcement purposes provided for in a wide range of enactments. Section 30 is engaged if the information is held for the purposes of criminal investigation or prosecution. Section 31 is engaged only if a prejudice test is satisfied; essentially, if disclosure would, or would be likely to, prejudice investigation and subsequent enforcement activity.”

WS v (1) Information Commissioner and (2) North Lancashire PCT [2013] UKUT 181 (AAC) (09 April 2013)

Information affected

Section 30(1) covers any information held by a public authority for the purposes of actual or potential criminal investigations that the authority has the duty or power to conduct. Section 30(2) covers information obtained from confidential sources that has or may be used in criminal or specified civil proceedings conducted by the authority. Section 31 covers information not exempt under section 30, if its disclosure would, or would be likely to, prejudice prevention, investigation or enforcement of a range of criminal or civil matters.

Things that FOI Officers need to know (s.30)

  • Section 30(1) expires when the information becomes historical (ie after 20 years from 2022), but section 30(2) can be applied to older records (eg names of informants from early 20th century).
  • Public authorities must state which part of the exemption they are relying on (eg s.30(1)(a), (b) or (c) or (2)(a) or (b)).
  • 30(1)(a) can only be used by authorities with a duty to investigate offences.
  • 30(1)(b) applies where the public authority has the power to investigate offences but doesn’t have to. It can apply where the authority chooses not to pursue a criminal investigation but could have done.
  • 30(1)(c) covers information held by authorities for the purpose of criminal proceedings – ie deciding whether or not to prosecute or as part of the prosecution process itself (eg the Crown Prosecution Service).
  • 30(2) will cover things like information obtained from informants for criminal investigations; tip offs from witnesses that only came forward on the basis that they could remain anonymous; but also information collected by certain regulators from anonymous sources.
  • 30(2) will also cover evidence from undercover police officers, though the ICO suggests that it normally won’t apply to information provided by employees.
  • It will also cover procedures and protocols about the obtaining of information from confidential sources.
  • 31(2) lists a range of regulatory activities that can also benefit from the protection of s.30(2) – the effect of this is that, for example, the Health & Safety Executive can protect evidence received from whistleblowers.
  • A recent case outlined some of the relevant public interest arguments for withholding information under 30(1)(c) – and many of these arguments could apply to other parts of section 30 (see para 68 of linked decision): not wishing to deter people from assisting criminal investigations; vital interest in maintaining confidentiality so that there can be a full and frank exchange of views between police and the CPS; the CPS being able to communicate “frankly and fearlessly”. It concluded that it would be exceptional for the public interest in disclosure to overcome this need for confidentiality.
  • The Commissioner highlights another useful decision in this regard (see para 14 of linked decision) – it sets out four relevant factors:”(a) the stage a particular investigation or prosecution has reached, (b) whether and to what extent the information is already in the public domain, (c) the significance or sensitivity of the information requested and (d) whether there is any evidence that an investigation or prosecution has not been carried out properly which may be disclosed by the information…”
  • As with most exemptions, there is provision to refuse to confirm or deny whether relevant information is held as necessary.

Things that FOI Officers need to know (s.31)

  • If you’re using section 30, you can’t use s.31 (unless you are neither confirming nor denying whether information is held).
  • “Law enforcement” is a very loose term to describe a long list of “activities and purposes which go beyond actual law enforcement” according to the Information Commissioner’s guidance.
  • This is a prejudice-based exemption – so you have to demonstrate that disclosure would, or would be likely to, prejudice law enforcement. You should set out what prejudice you envisage (p6) – in other words, the harm that disclosure may cause. The widely accepted approach to this is set out in Hogan v IC, and summarised in the Commissioner’s guidance. You must remember to state how likely you consider the prejudice to be – choose between “would” and “would be likely to”.
  • prejudice can be direct or indirect (see para 10 of linked decision).
  • Section 31(1) consists of a long list of things that might be prejudiced by disclosure – effectively s.31 is a list of mini-exemptions.
  • The most significant are: prevention and detection of crime, apprehension and prosecution of offenders, administration of justice, assessment of tax, immigration controls, security of prisons.
  • 31(1)(g) – (i) cover the exercise of a public authority’s functions, civil proceedings, and fatal accident inquiries, for any of the purposes listed at s.31(2). The effect of this is that if prejudice to a range of regulatory functions would or would be likely to be caused by disclosure, the exemption applies.
  • 31(2) includes such broad descriptions as “the purpose of ascertaining whether any person is responsible for any conduct which is improper” – so for example, internal investigations into councillors’ interests and expenses, or disciplinary investigations into employees, are likely to be covered.
  • The Voyias case concerned a request for a list of empty properties, and at the second attempt, the First Tier Tribunal concluded that the exemption applied due to the direct and indirect consequences of squatters using the list to identify suitable properties. They then listed a number of public interest arguments in support of withholding the information that may be useful in other cases: the inherent public interest in crime prevention; the cost of repair and security; eviction costs; impact on those affected; the impact on the surrounding community; impact on public officials and their work.
  • As for s.30 and most other exemptions, public bodies can neither confirm nor deny whether information is held.

Things that requesters need to know

  • In particular, it will be difficult to argue for the disclosure of information that falls under section 30 of the Act – as set out above, there is seen to be a strong public interest in maintaining the confidentiality of this kind of information.
  • Tribunals have said that there would be a public interest in disclosure if the information showed an “attempt to cover up wrongdoing” (para 68 of linked decision).

Essential case law

Recommended reading

  • Investigations and proceedings (section 30), Information Commissioner’s Office, 30 May 2013, version 1.0
  • Law enforcement (section 31), Information Commissioner’s Office, 29 May 2013, version 1.0
  • Wadham, K. Harris and G. Peretz (2011), Blackstone’s Guide to The Freedom of Information Act 2000, 4th ed., OUP, pp.125-130

If you’d like to explore these exemptions in more detail, Paul Gibbons is running a new workshop on the Freedom of Information Exemptions for Act Now Training this Autumn.