13. - (1) A person in a public place commits an offence if he- (a) wears an item of clothing, or (b) wears, carries or displays an article, in such a way or in such circumstances as to arouse reasonable suspicion that he is a member or supporter of a proscribed organisation. (2) A constable in Scotland may arrest a person without a warrant if he has reasonable grounds to suspect that the person is guilty of an offence under this section. http://www.legislation.hmso.gov.uk/acts/acts2000/00011--c.htm#11 Other tidbits: 58. - (1) A person commits an offence if- (a) he collects or makes a record of information of a kind likely to be useful to a person committing or preparing an act of terrorism, or (b) he possesses a document or record containing information of that kind. (2) In this section "record" includes a photographic or electronic record. (3) It is a defence for a person charged with an offence under this section to prove that he had a reasonable excuse for his action or possession. 89. - (1) An officer may stop a person for so long as is necessary to question him to ascertain- (a) his identity and movements; (b) what he knows about a recent explosion or another recent incident endangering life; (c) what he knows about a person killed or injured in a recent explosion or incident. (2) A person commits an offence if he- (a) fails to stop when required to do so under this section, (b) refuses to answer a question addressed to him under this section, or (c) fails to answer to the best of his knowledge and ability a question addressed to him under this section.