Assistant Commissioner Mark Rowley from the Met said: "We've taken a fresh look at policing London and London's obviously a world city.
"The recent census has shown what a big proportion of people in London come from far-flung places...It's important to us to be able to deal equally well with them as local offenders."
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Police have stepped up patrols after a woman in her 40s was "dragged to the ground" in a park in east London.
Families living near Heathrow say they are supporting a group of activists facing jail for chaining themselves to the airport's runway.
Police were called to break up a "large fight" which involved a baseball bat, a man dislocating his shoulder and three arrests.