The Sack Parliment demonstration resulted in totally unfounded violence and arrests. From the very start, the police did everything they could to keep people from even getting there. They turned people away at the underground station, they escorted the samba band away, they threatened and searched anyone who showed up alone before it started, and there's speculation that they had drivers make the road to the event unwalkable (it's never been this outrageously hard to cross before). From there, people were penned in, unable to leave, while a cop on a loudspeaker told us that our continued presence there was a crime. But it gets more Orwellian. The white sheets handed out to inform people that what they were doing was an arrestable offense? The cops made sure everyone had them, by handing them to people as they were let OUT of the pen at the end of the day. A man in a suit dropped by for his lunchbreak, and wasn't let out until 5. People were beaten, punched, repeatedly shoved, pepper-sprayed, and some were severely injured. Had the numbers on the side of the protesters been bigger, this would have been a lot harder for them to do. As it stands, it was a disaster.
I would like to clarify, however, that people shouldn't be scared away from future demonstrations by this disgusting display. These sort of attacks are generally uncommon on such a scale in anti-war protests, and ostensibly resulted from the location. And, had we enough protesters, this wouldn't have been possible.