The IPCC has announced they are investigating the arrest of a 20 year old man by the British Transport Police.
During the arrest officers used a spit guard at the London Bridge Station on July 21st 2016.
The BTP has referred the incident voluntary to the IPCC.
The IPCC investigation will consider whether the police use of force, the arrest and the method of restraint, including the use of a spit guard, were proportionate, necessary and in line with BTP policies.
IPCC Commissioner Cindy Butts said: “This incident has generated a great deal of concern and debate among the public following footage released on social media and therefore it is important we launch an independent investigation to thoroughly examine what happened.
“This will include considering whether this arrest and the use of this type of restraint was necessary in the circumstances. We have met with the man involved and we will be keeping him and all interested parties updated throughout the investigation.”