The incident happened in North Wharf Road near Paddington just after 12.20pm today (February 28).
Officers and London Ambulance Service crews attended and found a man who had been stabbed.
He was taken to hospital for treatment where his condition was assessed as non-life threatening.
No arrests have been made as police enquiries continue.
We have contacted M&S for further details on the incident.
A spokesperson for the Metropolitan Police said: “Police were called at 12:22hrs on Friday, 28 February following reports of a man being stabbed inside a shop on North Wharf Road, W2.
“The victim has been taken to hospital and his injuries are not believed to be life-threatening.
“Officers remain in the area and no arrests have been made at this stage. A cordon is in place at the location. ”
A spokesperson for London Ambulance Service said: “We were called at 12.20pm today (28 February) to reports of a stabbing on North Wharf Road, W2.
“We sent an ambulance crew and a paramedic from our tactical response unit to the scene.
“Our first paramedic arrived on scene in less than three minutes. We treated a man at the scene and took him to hospital.”
