He was awaiting assessment and had been placed in handcuffs, limbs restraints and a spit guard.
When the victim appeared to be resisting officers, PC Rhys Walmer sprayed PAVA – similar to pepper spray – in his face.
As officers continued to restrain the victim, PC Walmer then delivered 14 strikes with his baton to the arms and legs of the victim.
Hospital staff raised concerns with a police supervisor due to the level of violence used.
PC Walmer was later charged and at Snaresbrook Crown Court he was convicted of assault and administering a noxious substance (PAVA) with intent to injure.
Following his conviction, it was decided in June this year that PC Walmer should be dismissed without notice.
PC Walmer claimed he was insufficiently trained to deal with the situation but the Met Police rejected this suggestion.
Ch Supt Stuart Bell, in charge of policing for the East Area Basic Command Unit, said: “The level of force used by PC Walmer was not proportionate or necessary and his actions have been subject to proper scrutiny and accountability through the legal process.
“I would like to thank the hospital staff for quite rightly raising their concerns with the officer’s supervisor.
“All officers must be held account for their actions, especially when it comes to use of force. Those found to be using excessive use of force, like PC Walmer, will be brought to justice.”
