declar repres govern member state meet council continu role custom servic note import wide rang function carri european commun custom servic task includ collect ec custom duti agricultur levi good come countri collect nation excis duti vat import appli ec nation licens quota regim enforc ec anim plant health standard collect statist intern trade appli restrict export enforc import prohibit restrict protect peopl ec custom servic involv seizur kilogram heroin cocain hard drug kilogram cannabi complet singl market bring custom servic fulfil duti fiscal control disappear intern border commun freight move member state travel cross border freeli danger illicit traffick sensit good advantag open european market recogn expect busi travel freedom movement consider account specif measur appli custom servic drug smuggl similar threat societi extent permiss nation commun law check unobtrus select highli target traffic greatest risk commun extern frontier effect control proportion risk ensur uniformli high technic standard cooper custom servic law enforc agenc strengthen custom cooper long histori back instrument prepar custom cooper council recommend mutual administr assist eec base napl convent custom mutual assist council regul eec custom mutual assist group mag set complement work exist mutual assist group mag promot closer cooper custom servic eec member state seek measur enhanc custom effect focuss gener custom problem result complet intern market work draft protocol napl convent work mag continu support group effort remain commit aim underli establish singl market custom plai import integr role