The European Arrest Warrant (EAW) is now widely used to secure the arrest and surrender of suspected criminals across the Union. The EAW has a key role to play in the fight against terrorism and in bringing those accused of serious crime to justice. This report draws attention to two recent developments relating to the EAW. Firstly, the EC Commission's recent report on the implementation of the EAW criticised Member States for inadequate or faulty implementation. Secondly, certain Member States' constitutional courts have found incompatibility with safeguards provided for their nationals. As a result, some legal uncertainty now surrounds the EAW. Until this is resolved the EAW may not be fully effective between Member States. Further, the adoption of other measures based on mutual recognition, such as the European Evidence Warrant, may be delayed. The report also makes available the written and oral evidence on these matters given by Mr Andy Burnham MP, Parliamentary Under Secretary of State in the Home Office.