You will need permission from your local council to preach, harangue, solicit, or canvass in a public place. This refers to conveying any advertising, religious or other message to any bystander, passer-by or other person, whether means of amplification are used or not.
You may also need this permit to convey to any bystander or person a message or any material that may jeopardise public order because it is offensive, insulting or that might otherwise encourage a breach of the peace.