What are synthetic drugs?
New, synthetic versions of harmful drugs, including synthetic opioids and synthetic cannabinoids, are increasingly found in UK’s illegal drug markets.

This Library briefing paper provides an overview of police powers to release suspects from custody under investigation and on pre-charge bail. It also discusses the two major reforms that pre-charge bail has undergone in the last decade, first in 2017 and then in 2022.
Police powers: pre-charge bail and release under investigation (410 KB , PDF)
When the police have arrested and detained a suspect but do not have the evidence to charge them, the suspect must be released. They can be released either on pre-charge bail (also known as police bail), “under investigation” (RUI) or with “no further action”.
Comparison of pre-charge bail and RUI |
||
Pre-charge bail |
Release under investigation (RUI) |
|
Authorisation |
Must be authorised by a custody officer. |
No authorisation required. |
Police monitoring |
Suspects are required to report to the police. |
Suspects may be asked to voluntarily attend further police interviews but are not required to. |
Conditions |
The police can impose conditions on suspects as part of pre-charge bail that can restrict their movement and who they associate with. |
No power to attach conditions. |
Time limits |
Strict time limits. Pre-charge bail is initially set for three months. Police can internally authorise extensions of pre-charge bail for up to nine months. |
No time limit. |
Court oversight |
Court approval required to extend pre-charge bail beyond nine months. |
No court oversight. |
The release of a suspect on pre-charge bail can allow more time for the police to continue their investigation into a case or time for the Crown Prosecution Service (CPS) to make a charging decision. Pre-charge bail can only be authorised if it is considered ‘necessary and proportionate’ for:
If the circumstances of a case do not pass the ‘necessary and proportionate’ test for pre-charge bail, then the suspect must be RUI.
Pre-charge bail was reformed in 2022 by schedule 4 of the Police, Crime, Sentencing and Courts (PCSC) Act. There were growing concerns that since 2017 – when pre-charge bail was last reformed – police had been using RUI to release a large number of suspects instead of pre-charge bail including in cases involving serious offences such as domestic abuse, sexual offences, and offences against children.
Stakeholders said this was putting victims at risk because the police do not have the power to impose conditions on RUI suspects. Concern was also raised that suspects were being left in ‘limbo’ and that cases were allowed to drag on for long periods without conclusion because there are no time limits on RUI.
To address this, the PCSC Act:
These reforms are expected to lead to a rise in the use of pre-charge bail.
The changes were met with broad support amongst most stakeholders, including victim advocates and policing stakeholders. Some voices have been more cautious about the changes. The Law Society said it was important to ensure that suspects do not get “routinely” put on bail for extended periods. The Magistrates’ Association argued that the underlying principles for all bail decisions should be a presumption for the least restrictive measures necessary.
Police powers: pre-charge bail and release under investigation (410 KB , PDF)
New, synthetic versions of harmful drugs, including synthetic opioids and synthetic cannabinoids, are increasingly found in UK’s illegal drug markets.
On Wednesday 25 June 2025, there will be an Estimates Day debate on the spending of the Ministry of Justice. This debate pack contains details of the latest estimates and previous expenditure, background material, and suggestions for further reading.
The Crime and Policing Bill 2024-25 is scheduled to have its report stage in the House of Commons on 17 and 18 June 2025.