This poll summary was emailed to me during the protest planning meetup and is quite encouraging.

In the past, when events have appeared to force a choice between security and liberty, most people have opted for security, generally by margins of around two-to-one. This time, there is a broadly even balance on most of the issues that we tested following Mr Miranda’s detention, but with signs of concern that the police may have overstepped the mark with Mr Miranda

What is unclear is whether this is a general shift toward more libertarian attitudes, or is it a more sympathetic position on account of Mr Miranda not being a terrorist?