Duncan v Jones [1936] 1 KB 218

A woman had been ordered not to start a public meeting by a policeman, who reasonably feared (based on past experience) that disorder would be created by the protest.

The court distinguish it from Beatty, saying that it has nothing to do with whether a protest can be stopped due to fear of other people causing disorder (Beatty answered that), and say that in this case, criminal damage and public disorder are part of the meeting and caused by those involved in it.

Given this, the police were entitled to prevent it occurring and arrest the woman concerned.