Shocking video footage has emerged showing the 47-year-old man being brutally beaten in a car park in Hounslow, on Wednesday afternoon.
People watched on while the person beat the victim to the ground using a huge stick.
After sustaining the blows, the man lay motionless on the ground, in Hounslow, on Wednesday (26) at 2 pm.
And the clip appears to show, while he was incapacitated, the attacker steals something from his pocket.
The police later confirmed the item robbed was a mobile phone.
A construction worker from a nearby tower block filmed the car park attack after hearing a commotion.
The shocked 21-year-old, from Essex, said: “I saw between four and five people attacking him.
“I was working about ten stories up on a building just opposite the road. I heard something kicking off so we had a look over the side.
“I was in complete shock. I couldn’t believe what I was seeing.
“We heard the screaming and had no idea what it could be. It was horrific to see, especially in broad daylight.”
Metropolitan Police and paramedics were called to the scene.
No arrests have been made and the victim’s injuries are not believed to be life-threatening, police said.
Members of the public intervened to help the victim.
A Metropolitan Police spokesperson said: “Police were called at around 14:00hrs on Wednesday, 26 June to Hounslow High Street following reports of a man being attacked by a group of males.
“The victim, a man aged 47, was attacked as he walked through an alleyway. He was beaten to the ground and assaulted with a stick.
“The suspect group fled, stealing the victim’s phone in the process after members of the public intervened.
“The victim was taken to the hospital. His injuries are not believed to be life-threatening.
“At this stage, there have been no arrests. Enquiries continue, led by the West Area Command Unit.”