An interlocutory appeal is an appeal brought against a court ruling made during criminal proceedings, before any final verdict is reached. It's a narrow and rarely granted remedy, but in the right circumstances it can prevent a fundamentally flawed trial from running to its conclusion. Understanding when an interlocutory appeal is available, who can bring one, and what grounds support it is essential knowledge for anyone involved in a serious criminal matter.
What makes an appeal "interlocutory"?
Most appeals in criminal law are brought after the trial is over: after a conviction, or after a sentence is imposed. An interlocutory appeal breaks that pattern. It interrupts proceedings midstream to have an appellate court review a specific ruling before the case continues.
The word comes from the Latin interlocutio, meaning a decision made in the course of a proceeding. In criminal law, the kinds of rulings that might attract an interlocutory challenge include a judge's decision to admit or exclude evidence, a ruling on the admissibility of a voir dire determination, or a finding on whether a trial ought to be separated. Not every ruling qualifies. Courts are cautious about permitting appeals that fragment proceedings or delay justice.
Who can bring an interlocutory appeal?
Both the prosecution and the defence can bring interlocutory appeals in Australian criminal law, but the rights differ and depend heavily on the jurisdiction and the nature of the ruling challenged.
In New South Wales, the Criminal Appeal Act 1912 (NSW) and the Criminal Procedure Act 1986 (NSW) set out the limited circumstances in which an interlocutory appeal lies. The prosecution has historically had slightly broader rights in some jurisdictions to appeal evidentiary rulings before a trial concludes, because a post-acquittal appeal by the Crown is constitutionally barred by double jeopardy.
For the defence, the concern is different. A defendant who interrupts a trial mid-stream faces tactical risks, and appellate courts look for compelling grounds before granting leave. Leave is required in virtually all cases.
Common grounds for an interlocutory appeal
The grounds that courts accept most readily tend to involve rulings that go to the structural fairness of the entire trial. A wrongly admitted confession that will dominate the prosecution case is a clearer candidate than a disputed piece of documentary evidence that carries modest weight.
Typical grounds include:
- A wrongful ruling that highly prejudicial evidence is admissible
- An erroneous decision excluding defence evidence that is critical to the case
- A stay application that the judge has wrongly refused
- A ruling on jurisdiction that, if wrong, would make the entire trial a nullity
Courts apply a two-stage test. First, they ask whether the ruling is one that can legally attract an interlocutory appeal at all. Second, they ask whether leave should be granted in the circumstances. An applicant must generally show that the ruling is attended by doubt and that proceeding without review carries a real risk of injustice.
How interlocutory appeals relate to other pre-trial rulings
It's worth distinguishing an interlocutory appeal from a pre-trial challenge. Some rulings can be challenged before the trial starts: a severance application, for example, is made and decided before the jury is empanelled. If a judge refuses severance and the defendant believes that ruling is wrong, the timing of any challenge matters. An appeal lodged before trial begins isn't technically "interlocutory" in the strict sense; it's a challenge to a pre-trial order.
The interlocutory appeal, by contrast, arises once the trial is already under way. That context changes the calculus. A trial in progress creates real costs: jurors are waiting, witnesses are present, and courts are protective of their own efficiency. Appellate courts won't grant leave simply because a ruling looks arguable. The error must be serious enough that continuing without review would likely cause a substantial miscarriage of justice.
The double jeopardy dimension for the Crown
One reason prosecutors seek interlocutory appeals in some cases is that their post-trial options are genuinely limited. If a ruling to exclude evidence leads directly to an acquittal, the Crown generally cannot appeal that acquittal. The double jeopardy principle blocks it. An interlocutory appeal, brought before the verdict, avoids that impasse entirely.
This dynamic means that evidentiary exclusions can take on special urgency for the prosecution. If a judge rules that a key piece of evidence is inadmissible during the trial, and the Crown forms the view that ruling is legally wrong, the only live option may be an immediate appeal.
Procedure and timing
Speed matters. An interlocutory appeal must be filed promptly, usually within days of the impugned ruling. Courts don't keep juries sitting indefinitely while an appeal is resolved. In practice, a trial may be stood over, or in some cases a jury discharged, pending an interlocutory decision.
The Court of Criminal Appeal in NSW has jurisdiction to hear these appeals. The applicant must file a notice of appeal, a supporting affidavit, and typically a written submission setting out the grounds. An expedited hearing is usually sought because the trial cannot safely resume until the appeal is resolved.
What happens if the appeal succeeds or fails
If the appellate court rules in favour of the appellant, the impugned ruling is set aside and the matter is remitted to the trial judge with appropriate directions. In some cases, this means a retrial before a fresh jury. In others, the original jury can resume.
If the appeal fails, the trial resumes on the basis of the original ruling. The losing party retains the right to raise the same ground on appeal after the final verdict, though the strength of that ground may be affected by how the trial ultimately resolved.
A defendant who succeeds at trial after losing an interlocutory appeal has no ongoing grievance. A defendant who is convicted can include the wrongly decided interlocutory issue as one ground in a full appeal against conviction.
Getting advice early
Interlocutory appeals are time-sensitive and technically demanding. A decision to bring one, or to oppose one, needs to be made quickly and with precise legal analysis. Ann Valos Criminal Law provides advice on evidentiary rulings, trial procedure, and appellate options for defendants facing serious criminal charges in New South Wales.