Newsletters Criminal Defence 5th Jan 2017

Defending Private Prosecutions

  1. Private prosecutions of crimes such as fraud and trademark or copyright infringement have become an increasingly important tool of litigation in the UK in recent years. A number of us at 2 Hare Court are currently acting in such cases, defending and prosecuting.  Whilst much has been written of late about how to bring a private prosecution, relatively little has made its way into print about defending such cases.  Whilst doing so will of course involve many of the same considerations as defending a prosecution brought by the CPS, there is an additional array of options that should be borne in mind.

Challenging a summons

2. All private prosecutions begin in the magistrates’ court with the laying of an information. Once laid, the court will consider     whether to issue a summons or a warrant under section 1 of the Magistrates’ Court Act 1980.  The leading case on the exercise of that discretion is R v West London Justices ex parte Klahn [1979] 2 All ER 221, which held that the court should consider:

i) Whether the ingredients of an offence known to the law are prima facie present;

ii) Whether the offence is ‘out of time’;

iii) Whether the court has jurisdiction;

iv) Whether the informant has the necessary authority to prosecute; and

v) Whether in all the circumstances the allegation is vexatious.

3. In practice however, because the laying of an information only needs to be served on the court, and the court is not required to allow the prospective defendant to attend and oppose the issue of a summons, these arguments are more likely to be raised in response to the issuing of a summons.

4. The options for those defending a private prosecution that appears to lack merit are to make written representations to the Crown Prosecution Service inviting them to take over the proceedings and stop them (or continue the proceedings in the name of the CPS); an application for judicial review of the decision to issue the summons (and, potentially, a refusal by the CPS to take over and stop (or continue) the case); an application to dismiss the summons; and an abuse of process argument.

5. These possibilities are not mutually exclusive; the target of a private prosecution might extend an invitation to the CPS and issue an application for judicial review in tandem, and hold the possibility of an application to dismiss and then an abuse argument in reserve. There are often sound reasons to pursue a letter to the CPS and/or an application for judicial review at the outset, not least because defendants in a private prosecution will very often be particularly concerned about the reputational damage involved in appearing in court for an application to dismiss or abuse argument to be heard.

6. All four possible routes share a number of features in common, and will involve an examination of the merits of the case and/or the extent to which the allegation has been brought vexatiously or improperly.

Merits of the case

7. The merits of the case are relevant both to the Klahn criterion that there must be a prima facie case of an offence known to the law before a summons can be issued, and to the ability of the CPS to take over a private prosecution and discontinue it.

8. The Supreme Court confirmed in R (Gujra) v CPS [2012] UKSC 52 the lawfulness of the CPS’ approach, which is to take over and stop a private prosecution if either the evidential sufficiency stage or the public interest stage of the Full Code Test is not met.

9. Any application to the CPS or for judicial review should therefore address the requirement for a prima facie case (without which the decision to issue a summons is wrong in law); an application to the CPS should also address the public interest, which shares features with an analysis of vexatiousness for the purposes of judicial review (see below).

10. A balanced and fair assessment of evidential sufficiency is crucial to retain credibility with the CPS and/or the Administrative Court; to avoid handing the private prosecutor an easy opportunity to rebut the submissions; and to meet the requirement for candour in judicial review.

11. There are certain public interest factors that will be particularly relevant in the case of a private prosecution: the CPS will be quicker to act where the prosecution interferes with an existing investigation or prosecution, or where the defendant has been cautioned or given a promise that he will not be prosecuted. Significantly, the CPS will also consider whether the private prosecution is vexatious or malicious, of which more below.

12. The private prosecutor has the right to reply to an invitation to the CPS to take over the case, and is able, as an interested party, to provide submissions in relation to any application for judicial review.


 13. An application to the CPS should consider vexatiousness in the context of the public interest, while an application for judicial review should consider vexatiousness as a bar to the issuing of a summons.

14. There are a number of lines of argument likely to be particularly relevant in private prosecutions:

 i) Improper purpose, where it would offend the court’s sense of justice for the prosecution to proceed; this will often involve the use of a prosecution to exert pressure in parallel proceedings;

ii) Entrapment, where the private prosecutor has encouraged the crime, or created the same mischief about which he complains;

iii) Previous proceedings, where the case has already been litigated elsewhere, particularly where the private prosecution constitutes a collateral challenge to a previous decision;

iv) Conduct of the prosecutor, who is subject to the same obligations of fairness (especially in the area of disclosure) as the public prosecutor.


 15. As is apparent, a defendant in a private prosecution can litigate on many fronts on the same or similar grounds. The tactical and cost implications of doing so will have to be carefully considered, but at the very least there is ample scope in the right case for a defendant to challenge the bringing of a private prosecution, and bring it to an end before anything as costly or damaging as a full criminal trial has to be contemplated.  The strict time limits for applying for judicial review, and the need to protect the reputations of those involved, make it imperative to seek specialist advice as soon as a summons is received.


Brian O’Neill QC

Sarah Przybylska

Lewis MacDonald

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