‘O, where is faith? O, where is loyalty?’ Some thoughts on the duty of loyal co-operation and the Union’s external environmental competences in the light of the PFOS case

Discusses, with reference to the European Court of Justice decision in European Commission v Sweden (C-246/07), the extent to which the duty of loyal co-operation limits Member States' activities in respect of shared competences.

Reviews the background to the case and reflects on the implications of the decision for the nature of the EU's external environmental competences, and for loyalty under shared competences. Assesses whether loyalty is a competence-conferring rule and considers the implications of the ruling for loyal co-operation.