Christoph Marthaler's new production relocates Wagner's masterpiece to an unidentified central European city, a decade or so after the second world war. This has predictably caused ructions in Germany where the Swiss director's work is the subject of ongoing controversy. While the transposition reminds us that the opera does, indeed, take place some years after a protracted military conflict, Marthaler comes close to overstating his case. What for Wagner is a point of detail in an internalised psychodrama becomes instead a central element.