No where to go .... kettling of crowds

See The Guardian 22nd December for a video taken from within a "kettle" imposed by the Metropolitan Police during the student fees protests.  Voices of protesters - which do not sound aggressive - can be heard saying that "we have nowhere to go" and "why push us" and "we are peaceful why aren't you."  It must only be a matter time before this tactic has fatal consequences caused by crush injuries or inability to breathe.  Law and Lawyers looked at "Protest" here.  The Guardian 19th December published the views of a doctor who warned of the possible consequences.