The Criminal Detention Database 2015-2022 combines in one place information on detention conditions in all 27 EU Member States as well as in the United Kingdom. It does not ‘rank’ countries, but informs – drawing on national, European and international standards, case law and monitoring reports – about selected core aspects of detention conditions: including cell space, sanitary conditions, access to healthcare and protection against violence. The database should be especially useful for judges and legal practitioners involved in cross-border cases.