The incident reportedly took place on August 5, at around 3.10pm, on a train travelling to London Victoria. British Transport Police said a 15-year-old girl was seriously sexually assaulted by a man on board the service, before he left the train at Gatwick Airport station. Detective Inspector Ciaran May said: “We’re launching an urgent appeal following a very serious incident on board a train this afternoon. I’d urge anyone who recognises the man in the photo to get in touch with us as soon as possible. "You can text us on 61016 or call 0800 40 50 40, quoting reference 469 of 05/08/26."