Police have released a shocking image of the injuries suffered by a 79-year-old man, after he was attacked near Tulse Hill in Lambeth.
The victim was walking along Thurlow Park Road at around 22:45 on Wednesday 3rd July, when he saw another man apparently threatening a woman.
He stopped to ask the woman if she was okay - and while she did not reply, the man then punched him in the face.
The suspect is described as being of Mediterranean appearance, around 5'8", of slim build, and in his mid 20s.
He was wearing dark coloured clothes, a high visibility waist coat, and was carrying a square red bag across his back.
The woman is described as Oriental.
Police are appealing for help to identify them.