It used to be unthinkable to start a dinner party without a satisfying ‘pop’ of the cork. But the popularity of ‘New World’ wines from Australia or America and the convenience of opening a picnic bottle without a corkscrew led to a rise in the popularity of screw caps. Now cork suppliers and environmentalists are fighting back claiming the move is threatening the two million hectares of forest across Portugal, Spain, North Africa and Italy which are sustained through industry management.