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."
Metropolitan Police Commissioner Sir Bernard Hogan-Howe said the body-worn video cameras being trialled would result in speedier justice for victims and help the force be "more accountable".
The commissioner said: "Our experience of using cameras already shows that people are more likely to plead guilty when they know we have captured the incident. That speeds up justice, puts offenders behind bars more quickly and protects potential victims.
"Video captures events in a way that can't be represented on paper in the same detail and it has been shown the mere presence of this type of video can often defuse potentially violent situations without the need for force to be used.
"I believe it will also show our officers at their best, dealing with difficult and dangerous situations every day but it will also provide clearer evidence when it's been alleged that we got things wrong. That has to be in both our own and the public's interest."
The head of the Metropolitan Police said it is vital police take action on the allegations resulting from the Ellison report into Stephen Lawrence's murder investigation.
The report concluded that a "police spy" had been working within the Lawrence family camp and that one of the officers in the original murder investigation may have acted corruptly.
Sir Bernard Hogan-Howe said: "This sort of allegation shocks me, it shocks my colleagues and it clearly shocked the public so it is vital that we take it seriously and do something about it."
Metropolitan Police Commissioner Sir Bernard Hogan-Howe has told ITV News that it was "pretty awful" to hear the findings of the report into Stephen Lawrence's murder investigation.
"As a professional police officer and then to see the reaction of Mr and Mrs Lawrence who were clearly distraught by what it had heard having lost their son so many years ago, at any level, human or professional, it is pretty awful to hear that list of terrible events," he said.
The head of the IPCC has apologised to the Lawrence family for the police watchdog's part in prolonging the "family's search for the truth".
The Independent Police Complaints Commission (IPCC) said it has asked the family of a Hillsborough victim if they would like it to investigate recent allegations made against the UK's most senior officer, Sir Bernard Hogan-Howe.
The IPCC wrote on Twitter:
Metropolitan Police Commissioner Sir Bernard Hogan-Howe has said the police do not yet have sufficient information to start an investigation into allegations of criminal activity relating to horsemeat contamination.