To allow prompt investigation creates a duty to do something, and that does not include waiting until the morning as that convenience does not outweigh the removal of a persons liberty! This again is carried out by a further independent person who must not only re-evaluate the evidence, but must also evaluate what has been done about it, and if nothing then there is no excuse to continue detention…

The Evidential Threshold for Continued Pre-Charge Detention in England

I. Introduction: Contextualising Pre-Charge Detention Reviews

1. Setting the Scene

The Police and Criminal Evidence Act 1984 (PACE) serves as the cornerstone of legislation governing the powers of police officers and the rights of individuals subject to police procedures in England and Wales.1 Enacted to codify and regulate police practices, PACE aims to establish a critical equilibrium between enabling the police to effectively combat crime and safeguarding the rights and liberties of the public.1 This balance is a central tenet of the Act, influencing procedures related to arrest, stop and search, investigation, and, pertinent to this report, the detention of suspects.1 Accompanying the Act are the PACE Codes of Practice, issued by the Home Secretary under the authority of Section 66 of PACE.4 These Codes provide detailed, practical guidance that police officers must follow when exercising their powers, ensuring consistency and adherence to the principles enshrined in the Act.1 Code C, in particular, addresses the requirements for the detention, treatment, and questioning of suspects held in police custody.1

1. The Concept of Pre-Charge Detention

Following a lawful arrest, PACE permits the police to detain a suspect at a designated police station for a period without bringing formal charges.2 This power is not unfettered; detention is intended to allow police necessary time to conduct investigations, gather evidence, and question the suspect regarding their involvement in the offence for which they were arrested.8 However, recognising the significant infringement on liberty that detention represents, PACE imposes strict time limits and mandates regular reviews of the necessity for continued detention.7

1. Focus of the Report

This report provides a detailed legal analysis of the specific test that must be satisfied for the lawful authorisation of continued detention of a suspect before they have been charged with an offence. The focus is squarely on the criteria applied during the periodic reviews of detention conducted by a designated ‘Review Officer’, as mandated by Section 40 of PACE and elaborated upon in Section 15 of PACE Code C.8 The analysis will delineate the necessary grounds for continued detention and crucially distinguish this standard from other relevant legal thresholds, such as the grounds for initial arrest or the standard required for charging a suspect.

1. Importance of the Test

The legal test applied during detention reviews is fundamental to the operational balance PACE seeks to achieve.1 It acts as a crucial safeguard against arbitrary or unduly prolonged detention, ensuring that individuals are not held in custody longer than is strictly necessary for legitimate investigative purposes. Simultaneously, the test must permit the police sufficient scope to pursue reasonable lines of inquiry diligently. The application of this test reflects the ongoing tension between the state’s interest in investigating crime effectively, which may necessitate detention, and the fundamental right of individuals to liberty. The review process, and the test applied within it, serves as a key mechanism for navigating this tension, ensuring that the continued deprivation of liberty remains justified at specific intervals.

II. The Statutory Basis for Detention and Review

1. Initial Detention: The Custody Officer’s Role (PACE Section 37)

The process of detention following arrest commences under the authority of PACE Section 37. Upon an arrested suspect’s arrival at the police station (or immediately following an arrest at the station), the designated Custody Officer, typically an officer of at least Sergeant rank, assumes responsibility.8 Their first critical duty is to determine whether there is, at that point, sufficient evidence to charge the individual with the offence for which they were arrested.7

If the Custody Officer determines that sufficient evidence does exist, the suspect must either be charged or released (potentially on bail, for instance, to allow the Crown Prosecution Service (CPS) to make a charging decision).8 However, if the Custody Officer concludes that there is insufficient evidence to justify a charge at that time, the authority to detain the suspect is strictly limited. Section 37(2) stipulates that detention may only be authorised if the Custody Officer has reasonable grounds for believing that detention without charge is necessary either:

1. To secure or preserve evidence relating to an offence for which the person is under arrest; or
2. To obtain such evidence by questioning the person.8

This establishes the foundational ‘necessity’ threshold, intrinsically linked to active evidence-gathering related to the specific offence. If detention is authorised on these grounds, the Custody Officer must make a written record of the reasons for detention as soon as practicable, normally in the suspect’s presence.8 This initial justification based on investigative necessity is paramount, as it forms the basis upon which subsequent reviews will assess the continued lawfulness of the detention. The review process essentially re-evaluates whether this initial justification remains valid over time.

1. Reviews of Detention: The Review Officer’s Duty (PACE Section 40)

While Section 37 governs the initial authorisation, Section 40 of PACE mandates the periodic review of detention for suspects held in custody but not yet charged.8 The explicit purpose of these reviews is for a designated ‘Review Officer’ to determine whether the grounds justifying the detention, as established under Section 37(2), continue to apply.8 Detention cannot lawfully continue unless the criteria set out in the Act remain satisfied at the time of each review.

1. Procedural Detail: PACE Code C (Section 15)

PACE Code C provides the detailed operational procedures that police must follow regarding the detention, treatment, and questioning of suspects not detained under terrorism provisions.1 This Code, subject to periodic revision 1, translates the legislative requirements of PACE into practical steps for custody management. Section 15 of Code C specifically elaborates on the conduct of detention reviews mandated by PACE Section 40, outlining the timings, the personnel involved, the rights of the detainee, and the core considerations for the Review Officer.10 It is the primary source of guidance on the practical application of the legal test for continued pre-charge detention.

III. The Detention Review Process

1. Who Conducts the Review: The Role of the ‘Review Officer’

A critical element of the pre-charge detention review process concerns the identity and status of the officer responsible. PACE Section 40(4) and Code C Paragraph 15.1 specify that for reviews of detention before a suspect has been charged, the Review Officer must be an officer of at least the rank of Inspector.8 Furthermore, this Inspector must not have been directly involved in the investigation of the offence for which the suspect is detained.8

This requirement deliberately distinguishes the Review Officer from the Custody Officer (usually a Sergeant) who made the initial detention decision under Section 37.10 It also contrasts with the situation after charge, where the Custody Officer can conduct the reviews.10 The stipulation for a more senior officer (Inspector) who is detached from the investigation introduces a crucial layer of independent oversight into the pre-charge detention process. This structure is designed to ensure a more objective assessment of the continued necessity for detention, mitigating the risk of confirmation bias or undue influence from the investigating team. The involvement of a senior, uninvolved officer underscores the gravity of continued detention and reinforces the need for impartial justification before liberty can be further curtailed pre-charge.

1. Timings for Reviews

PACE Code C, Section 15, establishes a strict timetable for detention reviews to ensure that the justification for detention is reassessed at regular intervals 10:

• First Review: The initial review must be conducted no later than six hours after the detention was first authorised by the Custody Officer under Section 37.
• Subsequent Reviews: Following the first review, further reviews must take place at intervals not exceeding nine hours.

These timings apply specifically to the reviews conducted by the Inspector (or higher rank) for suspects detained pre-charge under the main provisions of PACE. While detention can, in certain circumstances (e.g., for serious indictable offences), be extended beyond 24 hours with the authorisation of a Superintendent (up to 36 hours total) 10 or beyond 36 hours with a warrant from a Magistrates’ Court 7, the fundamental test applied by the Inspector during the routine 6-hour and subsequent 9-hour reviews remains the focus of this report.

1. Right to Representations

A cornerstone procedural safeguard embedded within the review process is the detainee’s right to participate. Both PACE Section 40(12) and (13) and Code C Paragraph 15.3 mandate that before deciding whether to authorise continued detention, the Review Officer must, if practicable, give the following individuals an opportunity to make representations (orally or in writing) about the detention 8:

• The detainee themselves (unless they are asleep or incapable due to their condition or behaviour).
• The detainee’s solicitor, if they are available at the time of the review.
• The appropriate adult (required for juveniles and mentally vulnerable individuals), if they are available.

The Review Officer is obliged to consider any representations made.10 This right is not merely a formality; it provides a direct avenue for the detainee or their representatives to challenge the police assertion that continued detention is necessary and that the investigation is proceeding diligently. They can highlight potential delays, question the basis for necessity, suggest alternative means of achieving investigative goals, or raise welfare concerns. This participatory element transforms the review from a purely internal police assessment into a process where the detainee’s perspective must be actively considered, thereby strengthening the scrutiny applied to the justification for continued detention. Any comments made by the detainee during this process must be recorded in the custody record.10

1. Table: Pre-Charge Detention Review Schedule and Authorising Officers

The following table summarises the key stages, timings, and responsible officers involved in the authorisation and review of pre-charge detention under PACE:

Stage	Timing	Responsible Officer	Primary Legislation/Code Reference
Initial Detention Auth.	On arrival/arrest at station	Custody Officer (Sgt+)	PACE S.37; Code C S.3
First Review	By 6 hours post-authorisation	Review Officer (Insp+)	PACE S.40; Code C 15.1, 15.4
Subsequent Reviews	Intervals ≤ 9 hours	Review Officer (Insp+)	PACE S.40; Code C 15.1, 15.4
Extension Post-2nd Review	After 2nd review (permits up to 36 hrs total)	Superintendent+	PACE S.42; Code C 15.2
Further Extension	Beyond 36 hours (up to 96 hrs max)	Magistrates’ Court	PACE S.43, S.44; Code C 15.2 (refers to court authorisation needed)

Note: Ranks indicated are minimums. Insp+ denotes Inspector or above. Superintendent+ denotes Superintendent or above.

IV. The Legal Test for Continued Pre-Charge Detention

1. The Core Criteria (PACE Section 40(8) & Code C Section 15)

The substantive legal test that the Review Officer (Inspector rank or above) must apply when deciding whether to authorise continued detention before charge is set out in PACE Section 40(8) and reflected in the necessity considerations within Code C Section 15.8 The officer may only authorise further detention if they have reasonable grounds for believing that:

1. Detention without charge is necessary to secure or preserve evidence relating to an offence for which the suspect is under arrest; or
2. Detention without charge is necessary to obtain such evidence by questioning the suspect.8

This test directly mirrors the grounds upon which the Custody Officer initially authorised detention under Section 37(2).8 The review, therefore, serves as a confirmation that these specific investigative grounds persist and continue to justify the deprivation of liberty.

1. Analysing “Necessary”

The term “necessary” is pivotal. It implies a requirement that goes beyond mere convenience or preference for the investigating officers. The continued detention must be objectively required to achieve the specific evidence-gathering purposes outlined in the Act.8 If the evidence can reasonably be secured, preserved, or obtained without keeping the suspect in custody, then detention ceases to be necessary.

The necessity must relate directly to evidence concerning the offence for which the suspect was arrested.8 It cannot be justified on grounds unrelated to that investigation, such as a general belief that the suspect might commit unrelated offences if released (although such risks might inform decisions about bail conditions under separate provisions like PACE S.50A if bail were being considered 7). The Review Officer must be satisfied, based on the information presented (often by the investigating team), why continued detention, specifically, is required to progress the evidence gathering in relation to the investigated offence.

1. The “Diligence and Expedition” Requirement

Crucially, the necessity test does not operate in isolation. PACE Section 40(8)(b) imposes a concurrent and equally important condition: the Review Officer must also be satisfied that the investigation is being conducted diligently and expeditiously.8 This requirement is reinforced by guidance related to bail investigations, which also stresses the need for diligent progress.11

This means that even if securing further evidence is technically still necessary, continued detention cannot be authorised if the investigation has stalled due to inaction, inefficiency, or unreasonable delay by the police. Officers cannot simply detain a suspect and fail to pursue active lines of inquiry promptly. The ‘diligence and expedition’ limb ensures that the justification for detention is tied not only to the potential need for evidence but also to the active pursuit of that evidence. It imposes a positive obligation on the police to make tangible progress while a suspect’s liberty is restricted. A lack of demonstrable progress can undermine the justification for continued detention, forcing the Review Officer to consider release even if the investigation is theoretically incomplete. This prevents detention from becoming a passive holding measure and ensures it remains proportionate to the ongoing investigative activity.

1. “Reasonable Grounds for Believing”

The entire test hinges on the Review Officer having “reasonable grounds for believing” that the criteria (necessity and diligent investigation) are met.8 This establishes an objective standard. The belief cannot be based on mere speculation, gut feeling, or unsubstantiated assertions. It must be founded on specific, articulable facts, information, intelligence, or updates on the investigation presented to the Review Officer.17 The officer must be able to point to concrete reasons, grounded in the case’s current status, for concluding that continued detention is necessary and that the investigation is actively and efficiently progressing.

V. Distinguishing the Test from the Charging Standard

1. The Charging Standard: “Sufficient Evidence to Charge”

The decision to formally charge a suspect with a criminal offence engages a different and significantly higher evidential threshold than that required for continued pre-charge detention. Historically, PACE Section 37 simply referred to the Custody Officer needing to determine if there was “sufficient evidence to charge”.8 This standard was not defined within the Act itself and was often interpreted flexibly, sometimes seen as a relatively low bar, allowing charges to be brought pragmatically, particularly pre-dating the significant reforms introduced by the Criminal Justice Act 2003.19

Following these reforms and the establishment of statutory charging arrangements, the decision to charge is now primarily governed by the Crown Prosecution Service (CPS) and assessed against the two-stage test set out in the Code for Crown Prosecutors 16:

1. The Evidential Stage (The Full Code Test): Prosecutors must be satisfied that there is sufficient evidence to provide a “realistic prospect of conviction” against each suspect on each charge.16 This means that an objective, impartial and reasonable jury or bench of magistrates, properly directed and acting in accordance with the law, is more likely than not to convict the defendant of the charge alleged.19 This assessment involves considering the admissibility, reliability, and strength of the likely prosecution evidence, as well as the potential impact of any defence raised or likely to be raised.16
2. The Public Interest Stage: If, and only if, the evidential stage is met, the prosecutor must then consider whether a prosecution is required in the public interest.20 This involves balancing various factors for and against prosecution.

An exception exists in the form of the Threshold Test. This allows the CPS to authorise a charge when the Full Code Test is not yet met, but only under strict conditions: the suspect must present a substantial bail risk (necessitating an immediate charging decision to bring them before a court in custody), there must be reasonable grounds to suspect the person committed the offence, and there must be reasonable grounds to believe that further identifiable evidence is likely to become available within a reasonable period, enabling the Full Code Test to be met later.16

1. Contrasting the Standards

It is imperative to understand that the test for continued pre-charge detention (necessity for evidence gathering plus diligent investigation) represents a distinctly lower threshold than the “realistic prospect of conviction” required by the Full Code Test for charging.19 Detention can be lawfully authorised by the Review Officer precisely because there is not yet sufficient evidence to meet the charging standard, provided the detention remains necessary for the specific purpose of gathering that evidence, and the investigation is actively progressing.7 The focus of the detention review is on the investigative process, whereas the focus of the charging decision is on the likely outcome of a prosecution.

1. Rationale for the Different Standards

The existence of these different evidential standards at various stages of the criminal process reflects their distinct purposes and the escalating intrusion on individual liberty:

• Arrest: Requires reasonable grounds for suspicion that an offence has been committed.
• Initial/Continued Detention: Requires reasonable grounds for believing detention is necessary for specific evidence-gathering purposes related to that offence, coupled with diligent investigation.
• Charging: Requires a realistic prospect of conviction based on the available evidence (Full Code Test), or satisfaction of the strict Threshold Test criteria.

This graduated system acknowledges that investigations take time and evidence is gathered incrementally. However, it ensures that the justification for state actions against an individual becomes progressively stronger as the process moves from initial suspicion towards formal prosecution. The lower standard for authorising continued detention allows police the necessary, but controlled, time and opportunity to investigate offences thoroughly.8 Conversely, the higher charging standard protects individuals from facing the stress and stigma of a criminal prosecution where the evidence is weak or insufficient to realistically secure a conviction.19 This tiered approach is fundamental to how PACE attempts to balance effective law enforcement with the protection of individual rights.1

VI. Conclusion

1. Summary of the Test

The legal test for the authorisation of continued pre-charge detention by a Review Officer (an officer of at least Inspector rank not involved in the investigation) in England is twofold, as mandated by PACE Section 40(8) and reflected in Code C Section 15. The Review Officer must have reasonable grounds for believing that further detention is necessary eitheing** them. Concurrently, the Review Officer must also be satisfied that the investigation is being conducted diligently and expeditiously.

1. Key Elements

The application of this test involves several crucial components: a specific and objective necessity linked directly to evidence gathering for the offence under investigation; a requirement for demonstrable diligence and expedition in the conduct of the investigation; an objective assessment based on reasonable grounds by a detached Review Officer of appropriate seniority; and the vital procedural safeguard allowing the detainee and/or their representatives to make representations, which must be considered.

1. Distinction from Charging

This test, focused on investigative necessity and progress, must be clearly distinguished from the higher evidential threshold required for charging a suspect. The standard for continued detention permits lawful custody while evidence is sought, whereas the charging standard (typically the Full Code Test’s “realistic prospect of conviction”) demands a sufficient evidential basis to justify initiating formal court proceedings.

1. Final Thought

The test for continued pre-charge detention exemplifies the balancing act central to the Police and Criminal Evidence Act 1984.1 It provides police with the necessary authority to detain suspects for investigative purposes but subjects that authority to strict conditions, time limits, and regular, objective review. By demanding ongoing justification based on both the necessity of evidence gathering and the diligent pursuit of the investigation, the test aims to ensure that the significant infringement on liberty represented by detention remains purposeful, proportionate, and lawful throughout the pre-charge period.

Works cited

1. Police and Criminal Evidence Act 1984 (PACE) codes of practice – GOV.UK, accessed on May 5, 2025, https://www.gov.uk/guidance/police-and-criminal-evidence-act-1984-pace-codes-of-practice
2. Police and Criminal Evidence Act 1984: Full Printed Statute – Amazon UK, accessed on May 5, 2025, https://www.amazon.co.uk/Police-Criminal-Evidence-Act-1984/dp/B09S68C7W8
3. Police and Criminal Evidence Act 1984 – Wikipedia, accessed on May 5, 2025, https://en.wikipedia.org/wiki/Police_and_Criminal_Evidence_Act_1984
4. Draft Police and Criminal Evidence Act 1984 (Codes o – Hansard, accessed on May 5, 2025, https://hansard.parliament.uk/commons/2023-11-30/debates/695b5e2f-565c-49a0-89bf-22f5a795ecc4/DraftPoliceAndCriminalEvidenceAct1984(CodesOfPractice)(RevisionOfCodesABCDAndHAndNewCodeI)Order2023
5. POLICE AND CRIMINAL EVIDENCE ACT 1984 (PACE) – CODE C REVISED CODE OF PRACTICE FOR THE DETENTION, TREATMENT AND QUESTIONING OF – GOV.UK, accessed on May 5, 2025, https://assets.publishing.service.gov.uk/media/5d37219ae5274a400ce4c1cf/CCS0719598178-001_PACE_Code_C_2019_Print_Ready.pdf
6. PACE Code C 2023 – GOV.UK, accessed on May 5, 2025, https://www.gov.uk/government/publications/pace-code-c-2023
7. Police powers: pre-charge bail and release under investigation – UK Parliament, accessed on May 5, 2025, http://researchbriefings.files.parliament.uk/documents/CBP-7469/CBP-7469.pdf
8. Police and Criminal Evidence Act 1984 – Legislation.gov.uk, accessed on May 5, 2025, https://www.legislation.gov.uk/ukpga/1984/60
9. Police powers: pre-charge bail overview of the evidence (accessible version) – GOV.UK, accessed on May 5, 2025, https://www.gov.uk/government/consultations/police-powers-pre-charge-bail/outcome/police-powers-pre-charge-bail-overview-of-the-evidence-accessible
10. assets.publishing.service.gov.uk, accessed on May 5, 2025, https://assets.publishing.service.gov.uk/media/6580543083ba38000de1b792/PACE+Code+C+2023.pdf
11. Bail | The Crown Prosecution Service, accessed on May 5, 2025, https://www.cps.gov.uk/legal-guidance/bail
12. Pace Code C (Revised) – GOV.UK, accessed on May 5, 2025, https://assets.publishing.service.gov.uk/media/5f1a8f23d3bf7f5968d37dce/pace-code-c-2019.pdf
13. House of Lords – Delegated Powers and Regulatory Reform – Twenty-First Report, accessed on May 5, 2025, https://publications.parliament.uk/pa/ld200203/ldselect/lddelreg/122/12215.htm
14. Police and Criminal Evidence Act 1984, accessed on May 5, 2025, https://www.stmaryscentre.org/application/files/3514/7697/7405/PACE20198420FMERSA20201620JH.pdf
15. Pre-charge bail statutory guidance (accessible) – GOV.UK, accessed on May 5, 2025, https://www.gov.uk/government/publications/pre-charge-bail-statutory-guidance/pre-charge-bail-statutory-guidance-accessible
16. Director’s Guidance on Charging, sixth edition, December 2020, incorporating the National File Standard | The Crown Prosecution Service, accessed on May 5, 2025, https://www.cps.gov.uk/legal-guidance/directors-guidance-charging-sixth-edition-december-2020-incorporating-national-file
17. POLICE AND CRIMINAL EVIDENCE ACT 1984 CODE A CODE OF PRACTICE FOR THE EXERCISE BY: POLICE OFFICERS OF STATUTORY POWERS OF STOP A – GOV.UK, accessed on May 5, 2025, https://assets.publishing.service.gov.uk/media/5a7a3076ed915d6eaf154650/pace-code-a-2011.pdf
18. Police and Criminal Evidence Act 1984, accessed on May 5, 2025, https://sherloc.unodc.org/cld/uploads/res/document/gbr/1998/police_and_criminal_evidence_act_1984_html/Police_and_Criminal_Evidence_Act_1984.pdf
19. House of Lords – Constitution – Tenth Report, accessed on May 5, 2025, https://publications.parliament.uk/pa/ld200708/ldselect/ldconst/167/16708.htm
20. Charging and case preparation – College of Policing, accessed on May 5, 2025, https://www.college.police.uk/app/prosecution-and-case-management/charging-and-case-preparation
21. Director’s Guidance on Charging – The Crown Prosecution Service, accessed on May 5, 2025, https://www.cps.gov.uk/sites/default/files/documents/legal_guidance/Directors-Guidance-on-Charging-6th-Edition.pdf
22. revised code of practice for conditional cautions – adults – GOV.UK, accessed on May 5, 2025, https://assets.publishing.service.gov.uk/media/5a7ca762ed915d6969f4667e/9789999098144.pdf
23. Police and Criminal Evidence Act 1984 Part IV (Detention) – Legislation.gov.uk, accessed on May 5, 2025, https://www.legislation.gov.uk/ukpga/1984/60/part/IV