Hung juries and mistrials: what happens when jurors disagree

A criminal trial can end without a conviction or an acquittal. If jurors cannot reach the level of agreement the law requires, the result is a hung jury. The case is not decided, and the court must work out what comes next. This guide explains how deadlock is handled, how a mistrial differs from it, and when a retrial can follow.

What a hung jury means

A hung jury, sometimes called a deadlocked jury, is one that cannot reach a verdict on a charge after a proper period of deliberation. It does not mean the defendant has been cleared. It also does not mean they have been found guilty. Legally, the outcome is that there is no jury verdict on that count.

Deadlock can affect only part of a case. A jury may reach verdicts on some charges and fail to agree on others. The judge can take the verdicts the jury has reached and discharge the jury from the rest.

How judges try to break a deadlock

Judges do not usually accept a failure to agree at the first sign of disagreement. Jurors are normally asked to keep deliberating and may be reminded of their duty to consider the evidence carefully and listen to one another. They can also send written questions to the judge, who may repeat directions on the law.

In the United States, some courts use a supplemental instruction known as an Allen charge, after a 19th-century Supreme Court decision. It encourages jurors in the minority to reconsider their views and those in the majority to do likewise. Courts must be careful that such wording does not pressure anyone to give up an honest opinion, and appeal courts have reviewed its use closely.

Majority verdicts in England and Wales

In England and Wales, jurors are first asked to reach a unanimous verdict. If they cannot, the judge may later accept a majority verdict. The jury must have deliberated for a minimum period, which is at least two hours and 10 minutes, and the judge may allow more time depending on how complex the case is.

With a full jury of 12, the law generally allows a verdict if at least 10 agree. Smaller numbers are permitted if jurors have been discharged during the trial, and the required majority is adjusted accordingly. Jurors are asked in open court whether they have reached a verdict on which at least 10 of them agree. If that is not possible, the judge may discharge them.

Scotland

Scotland has a different system. A jury has 15 members and can return a verdict by simple majority, provided at least eight agree. Scottish juries can also return a not proven verdict, an option that does not exist in England and Wales.

The United States and unanimity

In federal criminal trials, a jury verdict must be unanimous. For many years some states allowed convictions on less than unanimous votes. In 2020, in Ramos v Louisiana, the US Supreme Court held that the Sixth Amendment requires a unanimous verdict to convict in serious state criminal cases. As a result, a single holdout juror can prevent a conviction in most American courtrooms, although the case may then be tried again.

Hung jury and mistrial: how they differ

A mistrial is the wider term. It means a trial is ended before a verdict because something has gone wrong or the proceedings cannot properly continue. A hung jury is one common cause, but there are others:

• serious juror misconduct, such as research on the case outside court;
• the illness or absence of a juror, judge or key participant, where a trial cannot continue;
• the disclosure of material that is inadmissible and highly prejudicial to the defendant;
• a significant procedural error that cannot be put right with a direction to the jury.

Either side may ask for a mistrial, and the judge decides. Before granting one, judges usually consider whether a lesser step, such as a warning to jurors or the removal of a single juror, would be enough.

What happens after deadlock

Once the jury is discharged, prosecutors decide whether to seek a retrial. They normally weigh the strength of the evidence, the seriousness of the alleged offence, the public interest and the effect on witnesses and victims of going through the process again. They may also decide not to proceed. The defendant stays presumed innocent throughout, and bail or custody decisions are considered again.

In England and Wales, a retrial after a hung jury is common in serious cases, but a third trial is unusual and generally needs strong justification. In the United States, the rules against double jeopardy do not normally stop a retrial after a hung jury, because the first trial ended without a decision. A retrial after a mistrial is more complicated. If the defence asked for the mistrial, a second trial is usually possible. If prosecutors deliberately provoked it to gain an advantage, a retrial can be barred.

A second trial is a fresh trial with a new jury. Evidence may be presented differently, and both sides have learned from the first hearing. Jurors in the second trial do not hear about the earlier disagreement.

Why the process matters

Jury systems balance two aims: convictions should rest on a high level of agreement, and a single juror should not be able to block justice indefinitely. Unanimity protects defendants. Majority verdicts reduce the risk of repeated deadlock and the cost and strain of repeated trials. A hung jury and a mistrial are not signs that the system has failed. They are safeguards that allow the court to stop, reconsider and, where appropriate, start again with a clean slate.