Horrified families were forced to evacuate from a playground after a man was stabbed nearby in a west London park on Saturday evening.
The 21-year-old was attacked metres away from where children were playing in Heston Park, Hounslow, just before 6pm on September 7.
Eyewitness footage shared on social media showed young children ducking under police tape as they were escorted from the area.
London's Air Ambulance was dispatched to the scene. However, the victim was later transported to hospital by road ambulance.
As of Sunday morning, Scotland Yard said that a knife had been recovered from the scene, but no arrests had been made.
The man's injuries, while not life-threatening, were described as potentially life-changing.
A Met Police spokesperson said: "Police were called at about 17:40hrs on Saturday, 7 September to reports of a man stabbed in Heston Park in Hounslow.
Emergency services attended. The 21-year-old man was taken to hospital by the London Ambulance Service. His injuries have been assessed as not life threatening but potentially life-changing.
"A crime scene is in place. A knife has been recovered. There have been no arrests and enquiries continue."
A spokesperson for the London Ambulance Service said: "We were called at 5.41pm yesterday (7 September) to reports of a stabbing in Heston Park, Hounslow.
We sent a number of resources to the scene including an ambulance crew and an incident response officer. We also dispatched London's Air Ambulance.
"The first paramedic arrived in less than six minutes. We treated a patient at the scene and then took him to a major trauma centre – by road – as a priority."
Authorities are urging anyone with information about the incident to come forward. Witnesses or those with relevant information are asked to call police via 101, quoting reference CAD 5734/07Sep.