Korostelev v. Russia, No. 29290/10, ECtHR (Third Section), 12 May 2020

The imposition of a disciplinary sanction to an inmate of Islamic faith who has carried out acts of individual prayer during the night, despite the regulation of the prison imposed him to sleep, constitutes a breach of article 9 of the ECHR.

Art. 9 ECHR
Art. 13 ECHR

1. The Court reiterates that, during their imprisonment, prisoners continue to enjoy all fundamental rights and freedoms, save for the right to liberty, Accordingly, on imprisonment a person does not forfeit his or her Convention rights, including the right to freedom of religion, so that any restriction on that right must be justified in each individual case, in the light of a proportionate balance with any competing interests.