A black pupil who was strip-searched after being wrongly suspected of carrying drugs is suing the Met Police.
The 15-year-old, also known as Child Q, is also taking civil action against her school, the law firm Bhatt Murphy said.
Scotland Yard has apologised after a safeguarding report found the search was unjustified and racism was “likely” to have been a factor.
Speaking via her lawyers, the girl said she wanted “cast-iron commitments to ensure this never happens again”.
In a statement, she said: “I want to thank the thousands of people across the world of all backgrounds who have offered me support – both publicly and through messages conveyed to my legal team – following everything I’ve been through.
“I know I am not alone.”
Hundreds of people attended a protest organised by Hackney Cop Watch at Stoke Newington police station.
During the incident, the girl was taken out of an exam to the school’s medical room and strip-searched by two female Met police officers searching for cannabis, while teachers remained outside.
No other adult was present and her parents were not contacted.
Her intimate body parts were exposed and she was made to take off her sanitary towel, according to the review. No drugs were found.
The victim’s mother told the safeguarding review that after the strip-search, her daughter had been “asked to go back into the exam” she had been sitting with no teacher asking about her welfare.
Her family said the girl had changed from “top of the class” to “a shell of her former bubbly self”, and she was now self-harming and required therapy.
One of Friday’s protesters told the BBC “she can’t even fathom” the “disgusting” treatment of the teenager.
She said: “What they did to that child has brought tears to my eyes every day because I’m thinking ‘could that have been my daughter once upon a time, could that be my granddaughter?”
London’s mayor Sadiq Khan has written to the head of the police watchdog urging them to consider a case of gross misconduct.
However, the Independent Office of Police Conduct (IOPC) said its investigation was complete and its report was being “finalised”.
It added three police constables had been served with notices last year advising them they were under investigation for misconduct, “over their roles in either carrying out the strip search or involvement in supervising it”.
Scotland Yard has said the officers’ actions were “truly regrettable” and it “should never have happened”.
Met Police Commander Dr Alison Heydari said: “While we await the findings of the IOPC investigation, we have already taken action to ensure that our officers and staff have a refreshed understanding of the policy for conducting a ‘further search’ and advice around dealing with schools, ensuring that children are treated as children.”
Source: BBC News. Headline photo: Protests were held over the teenager’s treatment at a north London police station