The European Union's top court has ordered the EU's intellectual property office to "reconsider" Kit Kat's bloc-wide trademark, prolonging Nestle's decade-long battle to claim exclusive rights over the chocolate bar's distinctive shape. Nestle has been locked in a blockbuster legal war with US rival Mondelez, maker of Cadbury chocolate, over the four-fingered wafer biscuit which was first sold in 1935. In a closely watched case, the European Court of Justice said the EU's intellectual property office must go back to the drawing board and revisit its 2006 to decision to grant Kit Kat an EU trademark based on its shape. The European Court of Justice in Luxembourg has ruled that the four-fingered shape of the KitKat chocolate bar is not distinctive enough to be trademarked.