Understanding the ‘Serve a Third’ Change in Law

The Sentencing Act 2026 (Commencement No. 6 and Revocation) Regulations 2026 bring into force changes to release arrangements for many prisoners serving Standard Determinate Sentences (SDS) in England and Wales from 1 October 2026. There are no eligibility criteria per se, instead all those serving SDS sentences will be released at the 33% mark of their sentence unless they are serving a sentence for an excluded offence. These provisions do not apply to those serving life sentences or extended determinate sentences.

Under the new arrangements, prisoners who are not serving sentences for excluded offences will generally spend less time in prison before release. Depending on the release provisions that previously applied, release may occur after serving one-third of the sentence instead of 40% or 50%, or after serving one-half of the sentence instead of two-thirds.

The changes do not apply to a range of excluded offences, which have been expanded following public outcry. These include manslaughter and other unlawful killing offences, rape and serious sexual offences, child sexual and grooming offences, offences involving indecent images of children, certain offences causing death by dangerous or careless driving, and child cruelty offences. The exclusions also apply to those convicted of an ‘attempt’ of any of the excluded offences.

The new release arrangements are being introduced in stages. Prisoners sentenced on or after 1 October 2026 are generally subject to the new rules immediately. For prisoners already in custody on sentences imposed before that date, implementation is staggered according to sentence length, with different groups brought within the new arrangements between 1 October 2026 and 8 June 2027.

If you are confused about the recent change in the law, or you have any issues relating to it, please contact the office on 0118 957 4018.

— by Charlie Jones charliejones@albinandco.co.uk