Violent arrest of a protester during #Nov9 by a large group of undercover cops

I witnessed this arrest while poutside of the kettle in Moorgate around 4PM. This was a large and planned operation. Before he was dragged out of the protest a line of police horses was formed to prevent protesters from following the cops. Undercover officers were intimadating people who tried to photograph the incident.
He was dragged to a small alley and police blocked it tto prevent any witnesses from coming in. The second part of the clip is when I run to the other end of the alley. There was around 10 coppers involved.