Telling the Jury That a Statement Is Void Does Not Breach the Right to a Fair Trial

In trials before the Jury Court, the management of void evidence raises issues that do not arise in the same way before a professional bench. When the deliberating body is a panel of lay citizens, a practical question immediately surfaces: can the presiding judge inform the jurors that a particular statement has no legal validity without that warning tainting their judgment? The Spanish Supreme Court has given a clear answer in proceedings 10454/2025.

The facts: a statement taken without a lawyer

The case arose from a jury trial for murder. During the investigation, the defendant had made a statement without the assistance of a lawyer — a safeguard the LECrim treats as non-waivable. That statement was excluded from the evidence as void. The question was then whether the presiding judge could expressly communicate that nullity to the jury, or whether doing so would introduce into the deliberation room something capable of biasing the jurors' decision.

The defence argued that the warning could create an unfavourable impression of the defendant — who had spoken at a point when she was unrepresented — and that, paradoxically, information about the nullity would thus end up acting as disguised incriminating evidence. The Supreme Court rejected that argument.

The Supreme Court's reasoning

The Second Chamber of the Supreme Court starts from a straightforward premise: the presiding judge's function in instructing the jury is not to conceal what has happened in the proceedings but to explain to jurors which evidential material they may assess and which they may not. Informing them that a procedural step is void forms a natural part of that instructional function and does not distort it.

The reasoning rests on two pillars. The first is the very purpose of excluding unlawfully obtained evidence: if nullity is declared so that the tainted step does not influence the court's decision, the most coherent course is for the lay tribunal to be told precisely which materials fall outside its assessment. Silence does not guarantee the jurors are unaware of the statement's existence; the explicit warning gives them a clear instruction to disregard it.

The second pillar is the right to a trial with full guarantees: that right protects the defendant against evidence obtained in breach of her rights being assessed — not against transparency in managing that evidence before those who must judge. There is no breach of Article 24 of the Constitution where the jury receives the correct instruction.

Handling void evidence before the jury

The ruling provides criteria applicable beyond the specific case. In jury trials, the presiding judge bears responsibility for establishing in the final instructions which pieces of evidence the jury may consider and which must be kept out of its deliberation. Where evidence has been excluded for nullity, the instruction must be express and precise: it must state that a particular step has no evidential value and that jurors must not take it into account when reaching their verdict.

This demand for clarity intensifies in cases where the void evidence was of some prominence during the investigation or was mentioned at various points during the trial. Unlike a professional bench — presumed to know the rules of exclusion and to apply them in its reasoning — the lay jury may not understand on its own why certain material does not feature among the evidence presented to it. The presiding judge's instruction fills that gap and is at once a guarantee of impartiality and of respect for the defendant's rights.

Cassation review in jury trials

The Supreme Court uses the ruling to recall the structure of cassation review in cases heard before the jury. Once the matter has passed through an appeal before the Superior Court of Justice, the role of the Second Chamber is narrowed: it does not review the proven facts or carry out a fresh assessment of the evidence. Its analysis is confined to checking whether the appeal judgment infringed the substantive criminal law or contained a procedural defect serious enough to cause nullity.

The presiding judge's instructions to the jury are open to cassation review only where it is shown that they breached a fundamental right — such as the right to a trial with full guarantees — or substantially altered the direction of the verdict. A formal criticism of an instruction or a disagreement about its precise wording does not, by itself, open that avenue.

Practical relevance for the defence

The doctrine set out in this ruling has direct practical interest for those appearing in jury trials. First, it confirms that excluding unlawful evidence is not completed by the mere decision to exclude it: it also requires an explicit instruction to the jury so that the nullity takes effect in the deliberation. The defence therefore has an interest in ensuring that instruction is clear, precise and given before the jury retires.

Second, the ruling removes the uncertainty about whether the warning to the jury can itself prejudice the defendant. The Supreme Court rules out that possibility: information about the nullity is not disguised incriminating evidence but a guarantee that the verdict is built on lawful material. Finally, the ruling is a reminder that the cassation route in jury cases that have already gone through appeal is narrow, and that grounds must be framed as a question of infringement of law or procedural nullity, not as a review of the evidence.