Police have released a CCTV image of a man they want to speak to about an attack on a pregnant woman at London Bridge station.
The incident took place at about 1240 BST on 17 September.
The victim, a 39-year-old woman from south Croydon, who was six months pregnant, was walking on a London-bound platform at the station.
She became involved in an altercation with a man, who then punched her in the face.
The suspect, who was accompanied by a blonde woman, was last seen boarding a Charing Cross-bound service from platform six of the busy station.
Investigating officer PC Clive Thomas said: "This was a particularly nasty and violent attack on a pregnant woman.
"She was taken to Guys Hospital following the assault and both she and her unborn child were checked out by maternity staff.
"Fortunately, the woman's baby was unharmed, although the mother was left very shaken and distressed by what took place."