8(1), it seems that some Member States have not yet fully transposed FD ESO into national law. Consequently, difficulties might arise when a supervision measure foreseen by an issuing State is found to be incompatible with the law of the executing State. The issuing State has the discretion to decide whether or not to invoke the ESO measures and there is no automatic legal right to the supervision order. However, since pre-trial detention has to be seen as a “measure of last resort”64 and must be used only if there are no other “less stringent measures”65 to achieve the pursued aim,66 it has been argued that courts have a legal obligation to consider the ESO as a suitable alternative to detention in cases of foreign nationals from an EU Member State.67 64 Lelievre v Belgium, App.no. 11287/03 (ECtHR, 8 Nov. 2007) para. 97. 65 Ladent v Poland, App.no.11036/03 (ECtHR, 18 March 2008) para.56. 66 Ambruszkiewicz v Poland, App.no. 38797/03 (ECtHR, 4 May 2006) para.31. 67 Fair Trials International (FTI), ´A Guide to the ESO´ (Fair Trials International, September 2012) available at http://www.fairtrials.net/documents/ESOguide, p.13 24