woman believed to be in her 50s sustained stab wounds to the head in an attack in Uxbridge.
Police responded to a call at 9:45am on Tuesday after reports a woman had been knifed near the junction of Church Road and Godfrey Avenue, UB5.
Officers found the woman with stab wounds to the head.
She was rushed to a local hospital after where she received treatment and she was later discharged.
The suspect has been described as a light skinned black man, aged from around 25 to 30 of slim build.
He is believed to be around 5ft 6 to 5ft 8inches tall.
At the time of the incident he was wearing a wolly hat, dark tracksuit, blue T-shirt and trainers.
Anyone with information is asked to call police on 101 quoting reference CAD1908/26Oct.
You can also contact police via Twitter @MetCC. To give information anonymously contact Crimestoppers on 0800 555 111 or online at crimestoppers-uk.org.