We are aware of a video showing part of an incident where a man was stopped and searched in Hackney in April.
On Wednesday, 22 April plain clothes officers were on proactive patrols in the area in response to ongoing gang tensions and recent violent incidents.
Three males on pedal cycles were requested repeatedly by the officers to stop; they did not.
An 18-year-old man was stopped for the purposes of a weapons search.
He was handcuffed and placed to the floor in an attempt to mitigate any potential issues should a weapon be present.
Following the completion of the search, no weapon was found and the man was allowed to go. He was not arrested.
Each stop and search is dealt with on its own merits at the discretion of the individual officers involved, taking into account various aspects including behaviour and compliance.
Officers have to make these judgement calls regularly on a daily basis, often in difficult circumstances.
They understand that their actions will be scrutinised as they go about their work and that the public have the right to hold them to account where appropriate.
A third-party complaint was received and assessed by the Directorate of Professional Standards. Following the assessment, a voluntary referral is in the process of being made to the Independent Office for Police Conduct (IOPC).
BCU commander Marcus Barnett, said: “I am aware that this footage has raised concerns in the community and of course the incident should be fully investigated. Given the public interest in this matter it is also appropriate that we voluntarily refer it to the IOPC.”