This guide is maintained as a current resource for September 2026 and covers only the laws of England and Wales. Information is for general guidance, not legal advice. Consult a qualified solicitor for advice specific to your situation.
A comprehensive guide to how appeals are reviewed for errors in custody time calculations in England and Wales, including remand time credit, statutory rules under the Criminal Justice Act 2003, appeal procedures in the Crown Court and Court of Appeal, the role of the CCRC, time limits and practical steps to challenge miscalculated custodial time.

In the criminal justice system of England and Wales, calculating the correct amount of custody time served - particularly time spent on remand before conviction and sentencing - is critical. Errors in these calculations can affect when a prisoner is released, whether a sentence is lawful, and whether the court applied the statutory framework correctly. There are established legal routes for reviewing and appealing custody time calculation errors, ensuring that individuals are treated fairly and in accordance with the law. This article explains how these reviews work, who can initiate them, the legal processes involved, time limits, and practical considerations for those affected.
Custody Time and Its Significance
When someone is held in custody while awaiting trial or sentencing - known as remand in custody - that time generally counts towards any later custodial sentence. The legal basis for this calculation is found in section 240ZA of the Criminal Justice Act 2003, which provides that remand time should count as part of the sentence for offences committed after 4 April 2005, provided the remand is in connection with the offence for which the sentence is later imposed. Time on remand can reduce the custodial term actually served in prison.
Errors in custody time calculations may arise through administrative mistakes, misinterpretation of remand periods, or judicial oversight - for example, when a court fails to credit remand properly during sentencing. Such errors can have serious consequences, including unfairly extending incarceration beyond what the law permits.
What Counts as Custody Time?
Remand in Custody
Remand in custody refers to the period when an individual is detained by court order while awaiting trial or sentencing. This period - once quantified correctly - will normally be deducted from the custodial sentence imposed at the end of proceedings. The prison service generally credits days spent in custody automatically under the statutory regime.
Exceptions and Special Circumstances
There are important nuances:
- Tagged bail with a qualifying curfew can give rise to partial credit for time spent under strict electronic monitoring, which courts must calculate at sentencing.
- Life sentences and other discretionary sentences require courts to take remand time into account when setting minimum terms; administrative deduction alone does not suffice.
Errors frequently arise when the court misunderstands how remand credit should be applied, or when administrative practices are inconsistent with the statutory framework.
Legal Basis for Appealing Custody Time Calculation Errors
Criminal Appeal Act 1968
If custody time was not properly credited in a Crown Court sentence, the defendant may appeal under the Criminal Appeal Act 1968 on the basis that the sentence was wrong in principle or unlawfully calculated. Appeals on sentencing can include challenges to how custody time was computed. A successful appeal can lead to variation of the sentence or reduction in the effective length of imprisonment.
Court of Appeal
The Court of Appeal (Criminal Division) is the primary forum for reviewing alleged errors in sentencing and custody time credit. Appeals must typically be launched within 28 days of sentencing, although extensions may be granted in circumstances where there are good reasons. Appeals focus on whether the original sentencing judge applied the correct legal principles and whether the custodial calculation was lawful and just.
- Notices of appeal and grounds must be filed in compliance with the Criminal Procedure Rules and established case law.
- If an appeal is granted, the court can quash or vary the sentence, including adjusting how remand credit is applied.
For convictions or sentences handed down by the magistrates' court, appeals against custody calculation would first lie to the Crown Court before any further appeal to the Court of Appeal.
Role of the Criminal Cases Review Commission (CCRC)
If a person believes that all regular appeal options have been exhausted, yet a custody time error persists, they may seek review from the Criminal Cases Review Commission (CCRC). The CCRC is an independent statutory body empowered to investigate alleged miscarriages of justice and to refer cases back to the appeal courts if there is a “real possibility” that a court will alter the conviction or sentence. This includes errors in custody time credit that have not been addressed on appeal - particularly where administrative or judicial oversight denied proper credit.
When CCRC Might Intervene
The CCRC reviews applications where:
- new evidence emerges regarding custody time served;
- there was a legal mistake in how remand credit was handled; or
- procedural failings in earlier appeal processes occurred.
There is no statutory time limit to make an application to the CCRC, but older cases can be more challenging due to documentary gaps.
The Appeal Process Explained
Step 1: Identifying an Error
An appellant or their legal representative must first identify that custody time was incorrectly calculated or omitted. This often involves comparing court sentencing remarks, prison service records, and statutory requirements under sections such as 240ZA of the CJA 2003.
Step 2: Filing a Notice of Appeal
For Crown Court cases, a notice of appeal and detailed grounds must be filed, raising the specific error in custody time calculation. If the original sentence did not reflect proper credit, the notice must articulate how and why this was legally incorrect.
Step 3: Permission to Appeal
In the Court of Appeal, applications for permission to appeal are reviewed. If granted, the appeal proceeds to a full hearing. Appellants may be represented by solicitors or barristers with expertise in criminal appeals.
Step 4: Full Hearing and Judgment
At the full hearing - typically before a panel of judges - the court considers submissions on legal principles and statutory interpretation. If the court finds that custody time was miscalculated, it may:
- reduce the sentence or adjust the release date;
- remit the matter back to be resentenced; or
- uphold the sentence if satisfied that no error occurred.
Where administrative calculation was incorrect - for example, failure to deduct remand time or fail to apply qualifying curfew credit properly - the court's judgment corrects that error.
Time Limits and Practical Considerations
Strict Time Limits
- For Crown Court sentences, appeal notices must normally be filed within 28 days of sentencing.
- Failure to meet these deadlines may still be remedied by requesting an extension, but the appellant must demonstrate compelling reasons for the delay.
Accuracy of Records
Ensuring accurate custody records is essential. Discrepancies between court orders, prison records and statutory definitions can form the basis for appeal arguments.
Legal Assistance
Expert legal representation significantly increases the probability of identifying errors and presenting effective grounds of appeal. Appeals on custody time calculations involve technical interpretation of statutes and practice.
Common Questions
Does remand time automatically reduce my sentence?
In most cases, remand time is credited automatically for imprisonment under section 240ZA CJA 2003, but courts must still ensure the credit applies correctly. Errors can be challenged.
What if my release date was wrongly calculated?
An appeal or CCRC referral can result in correction of release dates and adjustment of custodial terms.
Can time on remand under tagged curfew be credited?
Yes - where qualifying curfew conditions apply, the court must specifically calculate this credit at sentencing (distinct from automatic prison remand credit).
Key Takeaways
Errors in custody time calculations - particularly in crediting time on remand - can have significant implications for sentencing and release dates in England and Wales. The legal system provides structured review and appeal routes:
- Appeals against sentences to the Crown Court or Court of Appeal where errors in calculation are alleged.
- Independent review by the Criminal Cases Review Commission where conventional appeal routes have been exhausted.
- Judicial correction of errors, ensuring sentences comply with statutory requirements such as those in the Criminal Justice Act 2003.
Understanding these pathways and acting promptly with accurate records and legal guidance is crucial to ensure that custody time is credited lawfully and fairly.