Alright I've just watched again and I think you are referring to the bit around 40 seconds in.
You are correct that the riot police come from behind the normal officers.
I can't see any agression from the demonstrators before the push from the riot squad.
I'm not saying that people weren't trying to breach the cordon and take the planned route - I am saying that the police approach was disproportionate and overly aggressive.
The riot police were in evidence throughout the march, presumably as some kind of deterrent.
"My lot" were mainly families and college students and had no plans to breach any police lines.
( tangledupinblue hairy badge with moving eyes, Mon 4 Mar 2013, 14:27, 1 reply, 12 years ago)

This

(Bonzodog29 is an unemployed sponge of the worst kind, Mon 4 Mar 2013, 14:52, Reply)