According to the City of London police, it is an arrestable offence under the Public Order Act to carry a placard describing Scientology as a 'cult'. Anyway, according to today's 'Guardian', they have arrested a 15-year-old boy for doing so.
The 1936 Public Order Act was aimed at Oswald Mosley's Jew-baiting Fascist thugs and banned the wearing of unauthorised military-style uniforms and disorderly behaviour. Its 1986 descendant provides that
"5.—(1) A person is guilty of an offence if he —
(a) uses threatening, abusive or insulting words or behaviour, or disorderly behaviour, or
(b) displays any writing, sign or other visible representation which is threatening, abusive or insulting, within the hearing or sight of a person likely to be caused harassment, alarm or distress thereby."
It would appear, therefore, that the City of London police consider that a placard carried by a teenager at a peaceful demonstration outside a Church of Scientology saying "Scientology is not a religion, it is a dangerous cult" is likely to cause "harassment, alarm or distress" to Scientologists.
Unless Scientologists are far less robust than their usual behaviour leads one to think, they are far more likely to feel irritation, and maybe indignation, than alarm or distress.
Anyway, do we really want to live in a society where the expression of even mildly critical opinions of others' beliefs is treated by the guardians of the law as a potential breach of the peace?
If so we might as well shut our traps, cease blogging, and restrict our public comments to such uncontroversial observations as "Aarrgh" and "Gfrrrubh".
Roll on, brave new world!