Vigilantes and Entrapment

At a time when incessant cuts to police resources mean fewer officers on the streets and numerous reported crimes going uninvestigated, the media’s attention has been drawn to activists taking the law into their own hands. Tony Williams considers the line between dutiful citizenship and overzealous vigilantism – and why law enforcement is still better left to those trained and qualified to investigate crime.


In a democratic society there is an understanding that officials whose role it is to enforce the law will do so within its boundaries – after all, as dangerous as an offender may be, there is no greater danger to the public than when the police think they’re above the law. Despite this, there are those who are willing to go where the authorities cannot or will not in the belief that this is the only way to achieve justice.

Vigilantes come in many forms. There have been cases of journalists inciting crime for the sake of a good story (with serious consequences for some), online “paedohunters” posing as children to bait would-be groomers, real-life “superheroes” taking up costumes to tackle street crime, or even – as in one of my recent cases – Hackney Carriage taxi drivers who have taken it upon themselves to investigate and report private hire vehicles unlawfully plying for hire.

In all these cases, private citizens have set out to catch offenders in the act without any input or supervision from the police. This sometimes involves inciting someone to commit a crime to gather evidence against them when that person might otherwise not have offended.


In short, no. In R v Sang [1980] AC 402 it was held that entrapment is not a substantive defence which entitles the Defendant to be acquitted. This makes sense – a criminal offence does not cease to be a criminal offence just because the Defendant has been incited to commit it.

However, it can give rise to an argument that to proceed with the case would be an abuse of process, or alternatively that admitting the evidence would have such an adverse effect on the fairness of the proceedings that it ought to be excluded under s78 of the Police and Criminal Evidence Act 1984 (‘PACE’).


In the case of R v Looseley [2001] UKHL 53, the Defendant was asked by an undercover police officer to sell him wraps of heroin, which he did. The Defendant submitted that this was entrapment. It was argued that the proceedings should be stayed as an abuse of process or the officer’s evidence excluded on the basis that the officer’s actions went over and above what was proper.

Nicholls LJ made it clear (at para 26) that “the overall consideration is always whether the conduct of the police or other law enforcement agency was so seriously improper as to bring the administration of justice into disrepute”. He went on to outline a number of factors which may weigh in the balance:

  • The nature of the offence. More serious offending may require less orthodox methods of detection, but such methods for relatively low-level offending may be more open to criticism;
  • The reason for the particular operation. If there is a genuine desire to detect or prevent offending of that nature, the court will be quicker to excuse the methods used. If however the operation appears to be motivated by a vendetta or bad faith generally (e.g. some ulterior motive), there is clear impropriety;
  • The nature and extent of police participation in the crime. If there is a high level of inducement to commit the crime in question, or persistent efforts made to get the defendant to offend, this will weigh against the agents in question;
  • In assessing the weight to be attached to any inducement, the Defendant’s circumstances including their vulnerability should be taken into account. For example, a Defendant with mental health problems or a lack of appreciation of the English language might be more susceptible to inducement than someone of sound mind and perfect English;
  • The defendant’s criminal record. This is unlikely to be relevant unless it can be linked to any reasonable suspicion in their offending: “past crimes do not forever outlaw the criminal and open him to police practices, aimed at securing repeated convictions from which the ordinary citizen is protected”.

Essentially a distinction must be drawn between the offence being committed by a Defendant who would’ve committed the offence regardless of who was inciting them to do so and a Defendant who, but for the actions of the agent provocateur, would not have acted in that way.


The case of R v L(T) [2018] EWCA Crim 1821 concerned an allegation of attempting to meet a child following sexual grooming, contrary to s1(1) of the Criminal Attempts Act 1981 (NB: as to vigilantes and the difference between a criminal attempt and a completed offence, see this article by Benjamin Knight). In the first instance the Defendant had applied to stay the proceedings as an abuse of process on the basis that there had been entrapment, albeit by a private citizen posing as a child. The trial judge allowed the application and the proceedings were stayed.

On appeal, the Court of Appeal ruled that staying the proceedings was wrong. Burnett LJ ruled that at the heart of Looseley was the idea that courts should be unwilling “to approbate seriously wrongful conduct by the state” by allowing a prosecution where there had been state entrapment. However, Burnett LJ went on to say that a distinction should be drawn between the conduct of state agents and the conduct of private citizens when making a decision based on Looseley as to whether to stay proceedings.

However L(T) is not authority that there can be no entrapment if a private citizen is the one entrapping. Burnett LJ expressly observed (at para 32) that “the conduct of a private citizen may in theory found a stay of proceedings as an abuse of process”, and that “given sufficiently gross misconduct by a private citizen, it would be an abuse of the court’s process… for the state to seek to rely on the product of that misconduct”.

Burnett LJ commented that a useful starting point is to consider whether the same conduct would justify a stay of proceedings if carried out by a police officer. Respectfully, in some cases this will not be a helpful comparison. Where the informant is shown to have a vendetta against the Defendant or some other ulterior motive, it can be argued that this is a distinguishing feature of the case justifying departure from that usual starting point. Arguably police officers would be unlikely to share motivations comparable with those of a private citizen acting in bad faith, but any bad faith on the part of the police would render such conduct more improper as an abuse of their position.

In summary, the threshold to have proceedings stayed or evidence excluded where there has been entrapment by a private citizen is much higher than where there has been entrapment by a state agent – but is not insurmountable.


The Courts have repeatedly stated that where there has been entrapment bringing the administration of justice into disrepute, the proper course of action is to apply to have proceedings stayed as an abuse. Despite this, we have seen that there are cases of entrapment by private citizens in which the Court will be reluctant to stay the proceedings as an abuse of process. Additionally, in the Magistrates’ Court there is no jurisdiction to hear arguments that it would be unfair to try the Defendant – without recourse to the High Court, only arguments affecting the fairness of the proceedings themselves are available.

Despite this, in some circumstances it may still be possible to argue that the evidence should be excluded under s78 of PACE. In Looseley, Hutton LJ (at paras 42-44) approved a passage from R v Shannon [2001] 1 WLR 51 by Potter LJ and observed that if there is good reason to question the credibility of an agent provocateur or to doubt their evidence (e.g. because of manipulation or selective editing of any recorded evidence), that evidence can be excluded. In many cases this will prove fatal to the prosecution.

Raising this at a voir dire where there is clear evidence on the papers to support exclusion may be helpful in preventing the trial from starting, but such an argument may be best left until after the agent provocateur has given evidence. This way they can be cross-examined as to the integrity of the evidence they have to give and any agenda they may have in entrapping the Defendant.


If unsuccessful in having proceedings stayed or evidence excluded as a result of entrapment and if a Defendant is found guilty in the face of such evidence, entrapment can still amount to mitigation for the purposes of sentence (see Sang, per Fraser LJ at [447B]). Even where there has been insufficient abuse or unfairness, it stands to reason that an offence which only took place following entrapment should be treated less seriously than an offence which would have taken place regardless.


Following this line of authorities, it is much harder to have proceedings stayed or evidence excluded as a result of entrapment where the person who obtained that evidence is a private citizen. However, it is not impossible. There are many factors one can raise to highlight why it would be wrong to rely on the private citizen’s evidence in a given case, particularly where there is evidence of an axe to grind, an ulterior motive or sheer persistence in their efforts to make someone break the law.

Despite the ruling in L(T), Burnett LJ implored would-be vigilantes not to jeopardise criminal investigations by taking the law into their own hands. The message is clear: Defendants can’t expect to be acquitted just because the person investigating wasn’t authorised to do so. However, one wrong move by an agent provocateur and the proceedings may be stayed, or evidence may be excluded – along with all hope of securing a conviction.

In conclusion, unless you have a superpower with a brightly-coloured outfit and cape to match – or unless you’ve dedicated your life to fighting crime after witnessing the murder of your billionaire parents and have access to resources and training the likes of which the authorities can only dream –  it’s probably best to leave criminal investigations to the professionals.

Central Chambers has a criminal team with experience in all types of criminal and regulatory proceedings involving potential entrapment. To instruct our barristers, please contact the clerks.