The adoption of Mutual Recognition as the cornerstone of judicial co-operation in both criminal
and civil matters within the European Union has resulted in an extension of the EU acquis via
a range of legal instruments designed to give effect to the ‘area of freedom, security and justice’
as envisaged by the Treaty of Amsterdam. Two of these instruments - the Framework Decisions
on the European Arrest Warrant and the Surrender of Persons between Member States and, the
Mutual Recognition of Decisions involving Custodial Sentences and the Deprivation of Liberty
– raise important questions concerning sentence execution, material detention conditions and
the treatment of convicted detainees within the European Union’s prison systems as well as for
the wider application of the Mutual Recognition process itself. Beginning with an overview of the
activities of the Council of Europe in the field of detention conditions, an illustration of practical
and legal concerns raised by European institutions in this area is subsequently provided. The specific
problems faced by foreign detainees in European prisons are then analysed alongside an assessment
of their numbers. Thereafter, the development of EU legal instruments which impact on material
detention conditions for convicted prisoners within the European Union is described with particular
attention paid to the two Framework Decisions specified above. Against this backdrop, the article
concludes by highlighting that differences in EU member states material detention conditions and
modalities in sentence execution pose a range of potential problems for the operationalisation of
these instruments – problems which have a legal, practical and political dimension.