Unreliable Evidence - The Law and Protest

Clive Anderson presents the series analysing the legal issues of the day. Conflict between police and G20 demonstrators raised serious questions about the distinctions in law between our right to peaceful protest and police powers to prevent violence and disorder. What are the legal limits of our right to express dissent? Is it acceptable for police to use powers under the Terrorism Act to prevent demonstrations and is the police tactic of 'kettling' to control crowds actually legal?