The Metropolitan Police chief said a campaign launched to identify possible victims of female genital mutilation (FGM) "warns" people of the law.
Sir Bernard Hogan-Howe said: "They have an option to stop - the fact they bought a ticket to me is irrelevant.
"They should not be committing a serious attack on a child and they should not be breaking the law."
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Irish police have seized £32 million worth of cannabis hidden in farm machinery on board a ship docking in Dublin.
Revellers reportedly jumped from the upper level of the lakeside venue to escape the flames.
A bomb blast reportedly struck a refugee camp in Syria near the border with Jordan causing injuries and deaths.