The European court of human rights has ruled police acted legally when they arrested protesters planning to disrupt the 2011 royal wedding with a 'zombie picnic'. Eight of those detained for several hours that day had appealed to the ECHR claiming their right to liberty had been violated. The arrests were necessary, an ECHR statement said, to 'prevent the likelihood of an imminent breach of the peace, taking into account the crowd size, international interest and "severe" threat level on the day of the royal wedding'