Scotland Yard chief Cressida Dick today blamed social media for driving young children towards violence and murder.
The 57-year-old Metropolitan Police commissioner, who started working as Scotland Yard's first female chief nearly a year ago, has made tackling of violent crime a central part of her agenda.
Often trivial disputes between young people were escalating into murder and stabbings at unprecedented rates, she told The Times.
The goading of rivals on online message boards and video sites "revs people up" and normalises violence, she warned.
"There's definitely something about the impact of social media in terms of people being able to go from slightly angry with each other to 'fight' very quickly," Dick said.
"It makes (violence) faster, it makes it harder for people to cool down. I'm sure it does rev people up," she said.
Her comments came as she announced a new task force of about 100 police officers to tackle violent crime in London as fatal stabbings in England and Wales hit their highest levels since 2011.
Dick said stop and search operations are "likely to go on going up", adding: "We will be out on the streets more."