A 31-year-old man was taken to hospital after being wounded in a shoot out in Chiswick High Road on Saturday night.
Passers-by were forced to dive for cover as a gun man chased the victim from Power Road up towards The Gunnersbury pub. Witnesses said one of the chasing pair was waving a gun 'wildly' with at least five bullets being fired.
The shots are thought to have gone off outside the Chiswick Moran Hotel's Globe Bar at around 8.15pm, with local police and firearms officers racing to the scene and cordoning off the area between Oxford Road North and Silver Crescent.
A Police spokesman said: "A short time later a 31-year-old man presented himself to hospital with a gun shot wound to the arm. The man was subsequently discharged from hospital."
A man has been arrested on suspicion of possession of a firearm with intent to endanger life and remains in custody at a West London police station.
Detective Sergeant Paul Dempsey said: "I am aware of a 237 bus on the Brentford to Hammersmith route which was near the scene. It is likely that passengers on that bus will have witnessed something and I need them to come forward."
Ben Lawrence General Manager of the Globe Bar said: "Nobody at the hotel saw anything, police blocked off the road though which caused an issue for our guests coming in and out. I wouldn't have thought something like this would happen in this area, but it is still London after all."
Maristela Desa, 35, who lives opposite the Chiswick Moran Hotel said: "I'm absolutely astonished and shocked that this has happened just outside my flat, it's scary."
Whilst Luda Harina, Director of The Gunnersbury pub did not seem surprised that this sort of crime was going on in the local area, saying: "We had a live gig so no one heard anything, I'm not really surprised that there was a shooting, you hear about things like this happening every day. Chiswick used to be such a nice area but not any more I guess."
Trident officers are investigating the shooting. Anyone with information should call the incident room on 020 8733 4774. Or to remain anonymous call Crimestoppers on 0800 555 111