We gave approximately 140,000 police In England and Wales covering 58000 square miles- that's little more than 2 policemen for every square mile. Okay I know we have more than that in the city areas but still they are few in number compared with the numbers of troublemakers and streets to be covered.
In reality there is little the police can do unless they know exactly where the incidents are going to be.
What would you do differently if you were a policeman in one of these areas and saw 200 youths running down the streets, some with TVs under there arms, others throwing bricks etc?