In an opinion released today, an Advocate General of the European Court of Justice encouraged the ECJ to abandon the precedent established by the 2005 Marks & Spencer judgment, which permits cross-border corporate group tax relief in certain situations.  The European Commission argues that certain UK rules on group relief make it virtually impossible in practice for group relief claims to succeed.  The non-binding opinion disagreed stating, “[t]he contested UK rules go even further than is required by European Union law.”