Sedley LJ's opinion was as follows.
I am unable to see any lawful basis for the arrest or therefore the conviction... There was no suggestion of highway obstruction. Nobody had to stop and listen. If they did so, they were as free to express the view that the preachers should be locked up or silenced as the appellant and her companions were to preach.
Mr. Kealy for the prosecutor submitted that if there are two alternative sources of trouble, a constable can properly take steps against either. This is right, but only if both are threatening violence or behaving in a manner that might provoke violence.
Free speech includes not only the inoffensive but the irritating, the contentious, the eccentric, the heretical, the unwelcome and the provocative provided it does not tend to provoke violence. Freedom only to speak inoffensively is not worth having. What Speakers' Corner (where the law applies as fully as anywhere else) demonstrates is the tolerance which is both extended by the law to opinion of every kind and expected by the law in the conduct of those who disagree, even strongly, with what they hear.
From the condemnation of Socrates to the persecution of modern writers and journalists, our world has seen too many examples of state control of unofficial ideas.
A central purpose of the European Convention on Human Rights has been to set close limits to any such assumed power. We in this country continue to owe a debt to the jury which in 1670 refused to convict the Quakers William Penn and William Mead for preaching ideas which offended against state orthodoxy.
To proceed, as the Crown Court did, from the fact that the three women were preaching about morality, God and the Bible (the topic not only of sermons preached on every Sunday of the year but of at least one regular daily slot on national radio) to a reasonable apprehension that violence is going to erupt is, with great respect, both illiberal and illogical.
The situation perceived and recounted by PC Tennant did not justify him in apprehending a breach of the peace, much less a breach of the peace for which the three women would be responsible. No more were the Magistrates justified in convicting the appellant or the Crown Court in upholding the conviction. For the reasons I have given, the constable was not acting in the execution of his duty when he required the women to stop preaching, and the appellant was therefore not guilty of obstructing him in the execution of his duty when she refused to comply.
Although, therefore, the Crown Court's questions do not pose the key issue, I would answer both questions in the negative and allow this appeal.[1]