The European Court of Justice held that , though it was for the national court to ultimately answer the question , it was possible that collective action taken by workers to protect their interests could be unlawful .
Action infringed the employer 's interests under TFEU article 56 .
The European Court of Justice held that , though it was for the national court to ultimately answer the question , it was possible that collective action taken by workers to protect their interests could be unlawful because it infringed the employer 's interests under TFEU article 56 .