Eight officers are under investigation after a black woman was pinned to the ground and punched during an arrest, the Metropolitan Police has confirmed.
The woman has told the BBC she feared for her life, and says police subjected her to further violence in custody.
Two of the officers under investigation by the Independent Office for Police Conduct (IOPC) have been placed on restricted duties.
Details into the probe have been made public after a Newsnight investigation.
Mobile phone footage of the woman's arrest, which happened on 9 May after officers pulled over a car in south-east London, shows how several police officers physically restrained the young woman - who is a student in her 20s and had been a passenger in the car.
One female officer can be seen repeatedly striking the woman.
In a statement the IOPC said: "Eight officers have been served with notices advising them they are subject to investigation, with six officers at misconduct level and two officers at gross misconduct level."
Details of the IOPC probe into the treatment of the woman have been made public after an investigation by BBC Newsnight into the way she was handled during her arrest.
Janet - not her real name - told the programme she had been working on an essay and went to get a takeaway, where she met an old friend with whom she ended up driving to a cash machine.
While she was a passenger in the man's car, it was pulled over after officers allegedly noticed he had been driving erratically. The driver has since been convicted of drink-driving.
Janet told BBC Newsnight she was pulled out of the car by an officer before it had come to a complete stop: "I just remember things turning like they looked a bit radioactive to me because I couldn't... I knew that I was losing consciousness."
She says she told the female police officer who punched her that the officer holding her down was killing her. She says the female officer "smirked" and responded: 'If you can talk, you can breathe."
Janet was arrested on suspicion of obstructing a drug search. She says she was lifted up from the street by her handcuffs and her hair braids, causing hair to be ripped out of her scalp, and was carried to the police van.
Inside Lewisham police station, she was subjected to further violence during a strip search which happened in the presence of male as well as female officers - something against police regulations.
"They didn't even tell me they were going to strip-search me. It literally just happened when in the presence of the male and female officers with my cell door wide open, so people were passing."
She claims this was done to "humiliate me more - dehumanise me more".
Once stripped naked, Janet says she was subjected to more violence, during which one police officer punched her repeatedly "very, very, very, very hard - there was a lot of intensity in her".
Janet said she resisted as she had recently had surgery on her stomach, and was worried about the pressure they were applying to her while she was on the floor.
'Use of Force'
The tactics used in this arrest such as handcuffing, restraint and hitting, are known as Use of Force, and are all measures officers are permitted to take under certain circumstances.
However, senior police figures who have seen the video of the detention of the woman told BBC Newsnight the level of force and the number of officers applying it in this case, seem unusual.
BBC Newsnight has obtained Use of Force data from 37 out of the 44 police forces in England, Wales and Northern Ireland.
During the lockdown months of April and May, 27 out of the 37 police forces saw a rise in Use of Force, compared with the same months in 2019.
The Metropolitan Police - the UK's biggest force - saw a rise of 26% from 25,993 Use of Force incidents recorded in April and May 2019, to 32,705 in the same months in 2020.
Home Office figures for England and Wales show black people are approximately six times more likely to be subjected to Use of Force than white people - a disparity that does not apply to other ethnic minorities.
The woman whose story features in BBC Newsnight's report has not received an apology from the police. All charges against her have been dropped.
The Metropolitan Police said: "All police officers are fully aware that they will be asked to account for their actions. Officers are not exempt from the law, and nor would we wish to be.
"The Met continues to co-operate with the IOPC's investigation team to ensure that all the facts are established.
"Eight officers are under investigation in relation to this incident; two of whom have been placed on restricted duties."
The IOPC said: "Use of Force is an essential policing tool and like all police powers must be used properly, proportionately and responsibly.
"We are examining the circumstances of the woman's arrest and the Use of Force on her.
"Our investigation is also looking at the woman's subsequent treatment in custody. As part of the investigation, we have already taken a statement from the woman."
It added: "To uphold public confidence in the police complaints system, we are investigating the use of stop-and-search tactics in this incident and whether the actions of those officers were appropriate and proportionate and followed approved police policies.
"We are also investigating if racial profiling or discrimination played a part in the incident.
"This incident took place in public view late at night and was probably witnessed by passers-by and members of the public. We would ask anybody who was in the area that evening and saw police activity to get in touch with us."
Regarding the Use of Force figures, the Home Office told BBC Newsnight: "We are clear that all Use of Force must be reasonable, proportionate and necessary - and no-one should be subject to it based on their race or ethnicity."
And responding to the rise in Use of Force incidents, the National Police Chiefs Council said the fall in crime during lockdown gave police "breathing space to carry out pro-active operations against known criminals".
In a statement, it added: "We have also seen a notable increase in assaults against emergency services workers since the beginning of the pandemic, and officers have accordingly had to use non-verbal tactics against offenders.
"Any action of this kind would necessitate that a Use of Force form is completed, which would therefore show an increase of overall force used."