Abuse of Process and the Magistrates’ Court – An Expanded Jurisdiction?

Tony Williams analyses the High Court’s recent ruling in the case of Mansfield v DPP and the newly-opened path to abuse of process applications in the Magistrates’ Court.

Abuse of Process

Where a Defendant seeks to argue that the proceedings against them are an abuse of the court’s process, there are two limbs which can be argued:

  1. That in the circumstances the Defendant cannot have a fair trial; and/or
  2. That in the circumstances, including where the case has been brought oppressively or unfairly, it would be unfair for the Defendant to face trial at all.

If the Court is satisfied that the proceedings are an abuse of process on either of the above grounds, the proceedings will be stayed and will come to a halt.

Following the decision in Horseferry Road Magistrates’ Court, ex parte Bennett [1994] 1 AC 42, it has been understood that the Magistrates’ Court only had jurisdiction to stay proceedings under the first limb. In order to raise abuse of process under the second limb, the case either had to be adjourned for an application to stay proceedings to be heard in the High Court, or (in the case of an either-way offence) the Defendant would have to decline consent to summary trial in order to benefit from the jurisdiction of the Crown Court.

In Mansfield v DPP [2021] EWHC 2938 (Admin), the High Court has seemingly encouraged a more pragmatic approach. Mrs Justice May DBE held (at paragraph 20) that that on a close reading of Bennett, it was: “…evidently not Lord Griffiths’ intention to exclude from the magistrates’ jurisdiction all category 2 cases of abuse”.

At paragraph 31, she went on to opine that “Most cases falling within category 2 arising in the magistrates’ court will be suitable to be considered and determined in that jurisdiction”

As such, the exceptions to this jurisdiction are very narrow and possibly include only those cases where the state has misconducted itself in relation to extraditing a defendant – although Mrs Justice May DBE declined to offer a more precise definition of the exception.

Thus, magistrates’ courts have jurisdiction to consider staying proceedings as an abuse of process in cases including but not limited to those:



It is also worth exploring the substance of the argument in Mansfield itself. The Defendant was 18 years old and of previous good character. He was arrested for possession of cannabis and possessing a bladed article in a public place.

Prior to interview his solicitor was given an assurance by the police that, as long as the Defendant made admissions, he would be given a caution. Consequently, he made full admissions in interview. Following his interview and a further review by the police, the Defendant was charged instead of being offered the promised caution.

After making the ruling in relation to jurisdiction above, Mrs Justice May DBE went on to consider the principles set out in R v Abu Hamza [2006] EWCA Crim 2918. In that case, it was held that proceedings are not likely to constitute an abuse of process even where a prosecution promise has been broken “…unless (i) there has been an unequivocal representation by those with the conduct of the investigation or prosecution of a case that the defendant will not be prosecuted and (ii) that the defendant has acted on the representation to his detriment”

Despite this, there may be circumstances where proceedings are not an abuse if new facts have come to light which were not known at the time the initial promise was made. Further, even if the above preconditions are satisfied, a court may go on to find that the proceedings are not an abuse in the particular circumstances of the case.


Mrs Justice May DBE went on to conduct a balancing exercise of the competing factors weighing against and in favour of a stay in Mansfield’s case. The High Court ultimately took the view (at para 45) that “…in the particular circumstances of this case the public interest in holding a state official to their promise outweighs the public interest in seeing that an offence, albeit in this case a serious one, is prosecuted”

This decision makes it clear that there is no hard and fast formula as to when a broken promise by a state official will amount to an abuse of process even where the conditions in Abu Hamza are satisfied, but that there can be strong public interest arguments in favour of staying proceedings, even when the allegation is a serious one. 


The judgment in Mansfield will be a welcome finding for many practitioners. It stands to reason that any Court should have the jurisdiction to prevent an abuse of its own process. Mansfield helpfully affirms that magistrates (and District Judges) do have jurisdiction to investigate the legitimacy of any prosecution brought before them, and to stay proceedings instituted oppressively or unfairly. It will also save time and cost for clients who wish to argue an abuse of process whilst avoiding the complexities (and financial risks) of High Court litigation.

As an application to stay proceedings will often involve complex legal issues, it may be beneficial to ensure that the application is listed before a District Judge, as opposed to a lay bench. Where an offence is triable either-way however, a Defendant may still benefit from electing trial by jury and placing such arguments before a Circuit Judge who will bring their legal knowledge and experience to the case.

Applying to stay proceedings as an abuse of process can involve substantial research and complex legal argument, but with significant results for clients if successful. Any defendant who considers that they are being prosecuted oppressively or unfairly will benefit from legal advice and representation at an early stage to ensure that such issues are identified and raised as soon as possible.

Tags: caution, prosecution, abuse of process, fair trial, promise, police, private prosecution, entrapment, disclosure, investigation, criminal procedure and investigation act, Mansfield v DPP, autrefois convict, double jeopardy