I agree absolutely with RB's sentiments.Examples should be made of these cretins,before their thuggish and uncivilised behaviour causes the authorities to cancel and even actively prevent any future protest-marches ; you cannot now hold one near the Houses of Parliament already, so be careful not to throw away ALL of your hard-won priveleges and freedoms, young people of today !!
       In my opinion,anyone throwing a fire -extinguisher into a crowd,from the roof of a tall building, no matter how strongly they may feel about the issues about which they are protesting,should be " sectioned" and locked up indefinitely in Broadmoor.
      The result of these morons trying to injure or even kill people in authority isn't going to PREVENT the formation of a "Police State", it is going to CAUSE it !!!