Witness Intimidation (Section 51 Criminal Justice and Public Order Act 1994)

Criminal Justice and Public Order Act 1994, s.51

Either way
5 years' custody

Definition

A person commits an offence if (a) he does an act which intimidates, and is intended to intimidate, another person ("the victim"), (b) he does the act knowing or believing that the victim is assisting in the investigation of an offence or is a witness or potential witness or a juror or potential juror in proceedings for an offence, and (c) he does it intending thereby to cause the investigation or the course of justice to be obstructed, perverted or interfered with. (Criminal Justice and Public Order Act 1994, s.51(1)) A person commits an offence if (a) he does an act which harms, and is intended to harm, another person or, intending to cause another person to fear harm, he threatens to do an act which would harm that other person, (b) he does or threatens to do the act knowing or believing that the person harmed or threatened to be harmed ("the victim"), or some other person, has assisted in an investigation into an offence or has given evidence or particular evidence in proceedings for an offence, or has acted as a juror or concurred in a particular verdict in proceedings for an offence, and (c) he does or threatens to do it because of that knowledge or belief. (Criminal Justice and Public Order Act 1994, s.51(2))

Points to prove

Under s.51(1), a person
does an act which intimidates, and is intended to intimidate, another person (the victim)
knowing or believing that the victim is assisting in the investigation of an offence or is a witness or potential witness or a juror or potential juror in proceedings for an offence
intending thereby to cause the investigation or the course of justice to be obstructed, perverted or interfered with
Under s.51(2), a person
does an act which harms, and is intended to harm, another person, or, intending to cause another person to fear harm, threatens to do an act which would harm that person
knowing or believing that the victim, or some other person, has assisted in an investigation into an offence, has given evidence or particular evidence in proceedings for an offence, or has acted as a juror or concurred in a particular verdict
and does or threatens to do it because of that knowledge or belief

Witness Intimidation is an offence under s.51 Criminal Justice and Public Order Act 1994, which creates two offences. Under s.51(1), a person commits an offence if he does an act which intimidates, and is intended to intimidate, another person, knowing or believing that the victim is assisting in the investigation of an offence or is a witness or potential witness or a juror or potential juror in proceedings for an offence, and intending thereby to cause the investigation or the course of justice to be obstructed, perverted or interfered with. Under s.51(2), a person commits an offence if he does an act which harms, and is intended to harm, another person, or threatens to do such an act intending to cause fear of harm, knowing or believing that the victim or some other person has assisted in an investigation into an offence, has given evidence in proceedings for an offence, or has acted as a juror or concurred in a particular verdict, and does or threatens it because of that knowledge or belief. It is immaterial that the act is done, or the threat made, otherwise than in the presence of the victim or to a person other than the victim (s.51(3)), and the harm may be financial as well as physical (s.51(4)). Where the act and the knowledge or belief are proved, the intention under s.51(1) or the motive under s.51(2) is presumed unless the contrary is proved (s.51(7) and (8)). Maximum sentence: on conviction on indictment, imprisonment for a term not exceeding five years or a fine or both; on summary conviction, imprisonment for a term not exceeding six months or a fine not exceeding the statutory maximum or both (s.51(6)).

In practice

This is an either-way offence: it may be tried at the magistrates' court or the Crown Court. Mode of trial depends on the seriousness and the defendant's election. The suspect must be cautioned in accordance with Code C PACE 1984 before any questions about the offence are put to them. Interviews must be audio-recorded (Code E) or, for indictable offences, may be visually recorded (Code F).

Last updated 20 October 2026. Reviewed 20 October 2026

Mode of trial: Either way
Maximum sentence: 5 years' custody
Act and section: Criminal Justice and Public Order Act 1994, s.51
Power of arrest: A constable may arrest without a warrant anyone who is about to commit the offence, anyone who is in the act of committing it, anyone whom he has reasonable grounds for suspecting to be about to commit it or to be committing it, and, where he has reasonable grounds for suspecting that the offence has been committed, anyone whom he has reasonable grounds to suspect of being guilty of it, but only if he has reasonable grounds for believing that for any of the reasons in s.24(5) (including to prevent the person causing physical injury to any other person, to protect a child or other vulnerable person from the person, to allow the prompt and effective investigation of the offence or of the conduct of the person, and to prevent any prosecution for the offence from being hindered by the disappearance of the person) it is necessary to arrest the person (Police and Criminal Evidence Act 1984, s.24(1) to (5)).
Search on arrest: On arrest at a place other than a police station, a constable may search the arrested person if he has reasonable grounds for believing the person may present a danger to himself or others, and may search the arrested person for anything which he might use to assist him to escape from lawful custody or which might be evidence relating to an offence, where he has reasonable grounds for believing the person may have concealed such a thing on him (Police and Criminal Evidence Act 1984, s.32(1), (2)(a) and (5)); as the offence is an indictable offence, the constable may also enter and search any premises in which the person was when arrested or immediately before he was arrested for evidence relating to the offence (s.32(2)(b)); and a constable may enter and search any premises occupied or controlled by a person under arrest for an indictable offence if he has reasonable grounds for suspecting that there is on the premises evidence, other than items subject to legal privilege, that relates to that offence or to some other indictable offence connected with or similar to it, with the written authority of an officer of the rank of inspector or above (Police and Criminal Evidence Act 1984, s.18(1) and (4)).
Detention clock: A person shall not be kept in police detention for more than 24 hours without being charged, calculated from the relevant time, which in the ordinary case is the time of arrival at the first police station to which the person is taken after arrest (Police and Criminal Evidence Act 1984, s.41(1) and (2)(d)). As this is an indictable offence (which includes an offence triable either way, Interpretation Act 1978, Schedule 1), a police officer of the rank of superintendent or above responsible for the police station may authorise detention for a period expiring at or before 36 hours after the relevant time where detention without charge is necessary to secure or preserve evidence or to obtain it by questioning and the investigation is being conducted diligently and expeditiously (s.42(1)); a magistrates' court may issue a warrant of further detention for a period of not more than 36 hours (s.43(1), (11) and (12)) and may extend it, no extension being longer than 36 hours and none ending later than 96 hours after the relevant time (s.44(1) and (3)).
Source: www.legislation.gov.uk/ukpga/1994/33/section/51