R v Thomasz Mysiak

The Sentencing Act 2020 provides the ordinary mechanism for crediting custody abroad while awaiting extradition, but only where extradition precedes trial or sentence. Where sentence has already been passed, the statutory power lies with the Secretary of State under the Prison Act 1952 and is limited to custody in the extraditing country. The Court of Appeal retains an exceptional power to reflect foreign custody where the interests of justice require it. Relevant factors include the statutory scheme, the applicant’s responsibility for the circumstances, opportunities to avoid or reduce custody, and the finality of sentence. Finality outweighed fairness where the applicant absconded and contested extradition. The application was refused.

After a trial in the Crown Court at Kingston upon Thames, the applicant was convicted of conspiracies concerning prohibited weapons and ammunition. He was sentenced in his absence to concurrent terms of eight years’ imprisonment. After later arrests in Poland and the Netherlands, he was returned to the United Kingdom. He sought an extension of 682 days and leave to appeal against sentence, arguing that 117 days spent in foreign custody should be credited. The central issue was whether the statutory scheme permitted such credit and whether any exceptional power should be exercised.

Mr Justice Wall, giving the judgment of the court, refused the application for an extension of time and leave to appeal against sentence.

1. Statutory scheme. Section 327 of the Sentencing Act 2020 requires the court to specify custody days awaiting extradition where the relevant trial or sentence occurs after extradition. Sections 243 and 240ZA then ensure that specified days are credited towards the sentence. The statutory duty does not apply where sentence was imposed before extradition. Where a sentence has already been passed, section 49(3)(a) of the Prison Act 1952 gives the Secretary of State, rather than the court, power to direct credit. That power is limited to custody in the country from which the prisoner was returned. It could therefore potentially address the 17 days in the Netherlands, but not the 100 days in Poland.
2. Exceptional power. The court accepted that an exceptional power exists to reflect foreign custody where the interests of justice require it, referring to R v Stuart Layden [2025] EWCA Crim 659. The court therefore considered whether to exercise that power.
3. Interests of justice. The statutory allocation of responsibility weighed against intervention. The applicant had absconded before sentence and was therefore the author of the circumstances giving rise to the custody. He could have surrendered voluntarily in Poland, reducing the period of detention and avoiding the later period in the Netherlands. Although fairness favoured preventing excessive custody, the strong interest in finality of sentence outweighed it on these facts.
4. The exceptional power was not exercised, and the application was refused.

1. Court of Appeal (Criminal Division). The court refused the application for an extension of time and leave to appeal against sentence: [2025] EWCA Crim 1001.
2. Crown Court at Kingston upon Thames. Following trial, the applicant was convicted and sentenced in his absence. He was later sentenced to a consecutive six-week term for failing to surrender to bail.