The CPIA four Rs

The expansion

• R: Record
• R: Retain
• R: Review
• R: Reveal

What it is for

The four Rs sum up what an investigator owes to disclosure: relevant material, including anything pointing away from the suspect, is written down, kept, reconsidered as the case develops, and shown to the prosecutor.

The College of Policing's Investigation process guidance (December 2022, read 19 October 2026) says investigators must "record, retain, review and reveal the material to the defence via the CPS prosecutor", and closes its section on lines of enquiry with a "Remember" list of the same four words.

Where it comes from

Three of the four Rs are in the Act. Section 23(1) of the Criminal Procedure and Investigations Act 1996 (Crown copyright, read 19 October 2026) requires a code of practice designed to secure that information which "may be relevant to the investigation is recorded", that "any record of such information is retained", that other relevant material "is retained", and that it "is revealed to a person who is involved in the prosecution of criminal proceedings". Section 23(1)(a) requires that "all reasonable lines of inquiry are pursued".

The Code of Practice made under section 23(1), in force from 31 December 2020, says in its preamble that it "sets out the manner in which police officers are to record, retain and reveal to the prosecutor material obtained in a criminal investigation". Its paragraphs give each R its content:

• Record, paragraph 4.1: unrecorded relevant information must be put "in a durable or retrievable form". Paragraph 4.3: "Negative information is often relevant to an investigation. If it may be relevant it must be recorded."
• Retain, paragraph 5.1: "The investigator must retain material obtained in a criminal investigation which may be relevant to the investigation." Paragraphs 5.7 to 5.9 set how long.
• Review, paragraph 3.5: the investigator "should pursue all reasonable lines of inquiry, whether these point towards or away from the suspect". The word review is the College's.
• Reveal, paragraphs 6.2 and 7.3: retained material outside the prosecution case "must be listed on the appropriate schedule of unused material", and the disclosure officer "should draw the attention of the prosecutor" to anything that may meet the disclosure test.

When it is used

From the first entry in a pocket notebook. Paragraph 2.1 of the Code makes every investigator responsible for "recording information, and retaining records of information and other material".

This page is educational information about how officers are trained.

Read on this site

• Disclosure
• Key Cases on Disclosure and Evidence
• Evidence Gathering by Police
• The golden hour