Sentence Review and LO 1/2026: Why This Reform Opens No Route to a Reduction in Spain

Organic Law 1/2026, in force since 10 April 2026, has amended the Spanish Criminal Code in offences that come up very often: theft and fraud in their repeat-offender forms, the theft of mobile phones and the diversion of electricity. Every Criminal Code reform raises the same question for anyone already convicted: can they benefit from the new law even though their sentence is final and they are serving it? As a general rule the answer is yes, but only where the later rule is more favourable. And this reform is not: it only tightens. As criminal defence lawyers who assess sentence review under a more favourable criminal law, we explain in this guide what favourable retroactivity means, why LO 1/2026 does not trigger it, which sentences can be reviewed and what the procedure looks like.

The Principle of Retroactivity of the More Favorable Criminal Law

The starting point is a safeguard with constitutional footing. Article 9.3 of the Spanish Constitution declares that punitive provisions which are unfavorable or restrict rights cannot operate retroactively. Read the other way round, that same provision underpins the opposite rule: favorable criminal provisions do apply retroactively. What is harmful cannot look backwards; what benefits the person can.

Article 2.2 of the Criminal Code spells this out without ambiguity: criminal laws that benefit the offender have retroactive effect even if, when they come into force, a final judgment has already been handed down and the person is serving the sentence. It is one of the few real exceptions to the force of res judicata: the finality of the judgment does not prevent a later, more lenient law from reaching a sentence that is already being enforced.

What Changes With LO 1/2026 (And Why No Penalty Goes Down)

LO 1/2026 is not a wholesale overhaul of the Criminal Code but a selective amendment of nine provisions: Articles 22, 66, 80, 234, 235, 248, 250, 255 and 568. What matters here is that none of them lowers a sentencing range. All of them widen criminal liability:

• Theft (Art. 234.2 CP): the requirement that the accumulated value of the offences exceed 400 euros before a prison sentence can be imposed on a repeat offender is removed, so the aggravation now reaches more cases.
• Fraud (Art. 248 CP): the same repeat-offender clause is written into the provision, with a cross-reference to the circumstances in Article 250.
• Aggravated theft (Art. 235.1 CP): a new tenth paragraph punishes with one to three years in prison the theft of mobile phones and of other communication or bulk data-storage devices holding personal data.
• Recidivism and suspension (Arts. 22.8, 66.2 and 80.2 CP): previous convictions for minor offences now count where they make up an offence aggravated by repeat minor offending.
• Diversion of electricity (Art. 255.3 CP) and flammable substances (Art. 568.2 CP): two new aggravated offences.

Hence the conclusion, which is worth stating plainly: LO 1/2026 opens no route to reviewing a final sentence. Nor does its single transitional provision, headed "Applicable legislation", which merely restates the general rule - earlier conduct is judged under the law in force when it was committed, unless the new law is more favourable - without creating any review procedure. Anyone offering to obtain a sentence reduction under this reform is offering a step that leads nowhere.

There is, however, an immediate practical consequence pointing the other way: because the reform is harsher, LO 1/2026 cannot be applied to conduct committed before 10 April 2026, even if the trial takes place now. In pending theft or fraud proceedings involving previous convictions, if the prosecution calculates repeat offending using the new criteria on older conduct, the defence must object expressly.

Which Sentences Can Be Reviewed

The mechanism reaches both final sentences awaiting enforcement and sentences actively being served, even at an advanced stage. There are three essential requirements:

• A final judgment handed down under the previous law, whether already being enforced or yet to be enforced.
• A later, more favorable rule: the reform relied on must be objectively more beneficial for the convicted person in their specific case, not in the abstract. LO 1/2026 does not meet this requirement.
• An application: the review does not operate by itself; it must be requested and decided in an incidental proceeding.

No review lies where the penalty imposed also fits within the new framework — because the judge could equally have imposed it under the new law — or where the change affects only a part of the penalty range (for example the maximum) that has no bearing on the specific penalty actually fixed in the judgment.

Comparing the Penalties as a Block

A decisive technical point is how the old law is compared with the new one. The rule, settled in Spanish Supreme Court doctrine on earlier reforms, is that the comparison is made as a block and not provision by provision. In other words, the overall sentencing result that each set of rules would produce — taken as a whole, with its basic offence, its sub-types, its aggravating factors and its sentencing rules — must be weighed, and the more favorable one applied in full.

An important consequence follows: you cannot build an "à la carte" regime by taking the most beneficial parts of the old law and the most beneficial parts of the new one. When the more favorable set of rules is chosen, it applies in its entirety, with its advantages and any trade-offs. The defence's job is precisely to show, with the numbers of the case, that the new body of rules leads to a lower penalty.

An abstract example helps. If the final judgment imposed a penalty at the bottom of the range for the offence applied and a later reform lowers that minimum, the comparison usually favours the convicted person, because under the new law the court could not have imposed so high a penalty. By contrast, if the penalty imposed sits comfortably within the new framework — so that the judge could equally have set it under the reform — the review does not lie, even if the new law "sounds" more lenient. What matters is not the wording of the provision in the abstract, but the concrete result for the penalty already imposed.

This way of comparing is not a recent invention: it reflects doctrine long settled by the Spanish Supreme Court in the wake of earlier reforms and recorded in agreements of its Criminal Chamber, which on each major legislative change has spelled out how sentences under enforcement are to be reviewed. The defence relies on those criteria to frame the case correctly from the very first submission.

The Review Procedure

The review is dealt with in an incidental proceeding with a clear structure:

• An application to the sentencing court by way of a reasoned submission, with the side-by-side analysis of the previous rules and those of LO 1/2026 applied to the case.
• A hearing of the public prosecutor and of the convicted person, which is an essential safeguard of the procedure.
• A decision by reasoned order in which the court decides whether to review the sentence and, where appropriate, fixes the new penalty.
• A fresh sentence calculation and, where relevant, an update of the prison file to reflect the revised penalty.

The order resolving the review can be appealed under the terms the procedural law provides depending on the court that issued it. If the court refuses the review without properly weighing the greater leniency of the new rule, that refusal can be challenged; hence the importance of a well-built initial submission that closes off the comparative analysis.

Effects on Enforcement and Prison Benefits

A favorable review does not stop at lowering the figure of the sentence: it produces knock-on effects on enforcement. As the total penalty is reduced, the periods measured against it are recalculated:

• Access to leave permits and other variables that depend on time served.
• Progression to open conditions (third grade) and, where applicable, parole, whose timelines are projected onto the new penalty.
• Any consolidation or accumulation of sentences, if the reduction alters the calculation of the maximum enforcement limit.

The most drastic effect is immediate extinction: if the time already served equals or exceeds the new sentence, the penalty can be declared served at once. That is why a good review submission does not merely request the new penalty but expressly sets out each favorable collateral consequence, so the enforcement court reflects it in the file without delay.

Common Mistakes and Cautions

Sentence review looks straightforward on paper, but in practice it concentrates several risks. A few cautions are worth keeping in mind:

• Assuming every reform lowers penalties. It does not. A harsher reform such as LO 1/2026 opens no review at all, and applying for one only raises an expectation with no legal basis.
• Confusing abstract leniency with concrete leniency. The reform sounding more lenient is not enough: you have to show that, with the numbers in the judgment, the result is lower.
• Overlooking the prison effects. Limiting yourself to the new penalty without requesting the recalculation of timelines leaves much of the benefit untapped.
• Neglecting the deadline and the route of appeal against a mistaken refusal.

Each of these points justifies careful technical handling: what is at stake is not a procedural nicety but the actual time of deprivation of liberty.

Where to Find Specialist Assistance

Alonso Sala is a firm dedicated exclusively to criminal law, based at Calle Velázquez 27, Madrid, with coverage across the whole of Spain. We assess whether a final sentence can benefit from any later reform as the more favourable law, prepare the review application before the sentencing court and set out the effects on enforcement and prison benefits. We also act in pending theft and fraud proceedings involving previous convictions, where what is at stake is that the repeat-offender criteria introduced by LO 1/2026 are not applied to older conduct.