A tourist was repeatedly punched in the face after she rejected the advances of a man who followed her from a London Tube station.
The 60-year-old was attacked by a man in his late 20s on 10 March after she left Warwick Avenue station.
The Met said the victim had earlier “politely” rejected the man’s attempts to “chat her up”.
Detectives are now appealing for information to help trace the woman’s attacker.
As part of the appeal the victim, who does not wish to be named, released a picture of her injuries.
The attacker is described as white, aged 25 to 27, about 5ft 8in tall, with short brown hair and brown eyes.
He was wearing light-coloured trousers, a brown jacket and a black baseball cap.
The Met said after failing to chat up the victim he followed her as she walked along Warwick Avenue towards Formosa Street, near Paddington.
He then grabbed her from behind and repeatedly hit her in the face, leaving her needing surgery.
After being found by a passer-by she was taken to hospital.
Det Con Mike Reilly, said: “Warwick Avenue is a busy area, especially at 8pm on a Friday evening.
“Someone must have seen something and I’d appeal for anyone with information to come forward as soon as possible so we can bring the perpetrator to justice.”