A young man was badly beaten by two thugs in a main shopping street and is in a serious condition in hospital.
The Asian victim, in his early 20s, was punched and kicked by his attackers, believed to be Somalian, in South Road, Southall.
Officers cordoned off and closed the street from its junction with the High Street to opposite the old Himalaya Palace Cinema, near where the man is believed to have been found.
Officers discovered him unconscious and badly hurt at about 9.30pm on Wednesday.
He was rushed to a west London hospital where doctors say his injuries are not thought to be life threatening.
Police combed the area for hours conducting a forensic fingertip search for evidence.
Traders were not surprised when they heard about the beating
Mohammed Choudhery, 62, owner or Asia Kebab House nearby, said his two staff working at the time were too busy to see anything, but added: "This road is a terrible place.
"There are so many youths, I don't know where they come from.
"A lot of them take the mickey as they know they're so young that the police can't do much to them.
"I feel safe though as the police are always watching here and always come when there's a large crowd, but there definitely needs to be more patrols at night.
"It's strange this happened on a Wednesday night as usually the trouble is at the weekends.
"People often get attacked and robbed in the alleyway nearby.
"Some report it to the police but many are illegal and so are scared to talk to them.
"I've been here 40 years and I love Southall.
"By the community meeting and talking with the police I believe we will be able to solve these problems."
No arrests have been made and police are keeping an open mind about the motive for the attack.
* Anyone with information should call Ealing Police on 0300 123 1212 or contact Crimestoppers anonymously on 0800 555 111.