Someone knows what happened that evening and I am urging them not to remain silent but to come and speak to us. Your information will be treated in the strictest of confidence.
Likewise I am directly appealing to the family members and friends of those believed to be involved - if you have slightest indication the person you know may have been involved in this incident I encourage you to get them to hand themselves into the police.
Failing to do so will result in my officers pursuing them.
More top news
David Cameron said the Met proved it can "do more with less" and declined to criticise the Mayor of London for his water cannon spend.
A group of disabled activists threw toys and balls at him as he entered the conference.
A wet start to the week and the unsettled weather is set to continue over the next few days.