An angry commuter punched a pregnant woman in the stomach and grabbed her by the hair on a busy Tube station platform, police said.
The woman was making her way through a crowd on the Victoria line southbound platform at Finsbury Park station when she was attacked.
British Transport Police said she may have accidentally made contact with the man as she passed through the crowd.
He then approached her from behind and struck her in the abdomen, police said.
The victim, who had been trying to reach a quieter part of the platform, challenged the man, saying she was pregnant.
But he then pulled her hair, before other passengers intervened.
The man was white, aged in his 40s, tall and of a large build. He was balding and was wearing a hoodie and a black rucksack.
British Transport Police is appealing for information to identify the suspect. The attack happened between 9.10am and 9.15am on Monday last week.
Anyone with information is asked to call 0800 40 50 40, quoting reference 127 of September 24. Alternatively, call Crimestoppers anonymously on 0800 555 111.
