A pistol was found at the scene of an incident in which an officer shot a man in the stomach, the police watchdog has said.
The Independent Office for Police Conduct (IOPC) has been investigating the circumstances and it has confirmed the man was tasered before an officer fired one shot.
The watchdog said the 36-year-old man was shot in the abdomen and taken to hospital, but his injuries are not thought to be life-changing or life-threatening.
The IOPC said ballistic testing of a non-police issue firearm found at the scene confirmed it to be a BB calibre airsoft pistol.
The watchdog said it will gather and analyse a range of evidence, including body-worn video, CCTV and eyewitness accounts, as well as the initial accounts of police officers.
The IOPC’s regional director for London, Sal Naseem, said: “The discharge of police firearms are rare but when this occurs it is important a thorough and independent investigation takes place.
“We are working to establish all the circumstances surrounding the sequence of events which led to this man sustaining his injuries.
“Our investigation is still in its very early stages.”