London had to bring in the army largely because the private firm that had the contract to provide event security completely failed to hire enough security guards, and this became apparent far too late for London police to raise the necessary staff themselves. There were probably ways to avoid the army, but would have cost much more.
Would I be wrong in assuming that perhaps trained military personnel may be easier to deal with and more level headed than some plastic policeman with a weekend certificate in security and law enforcement?
Just putting it out there. It could be better than the alternative.
In Geneva(Switzerland) they tried to use military at protests some 20-30 years ago. Some people were killed, thing is military are trained to kill if they are being attacked.
As far as I know they haven't used military personnel after that...