British Transport Police is appealing for information after a child was assaulted on board a train.
A man travelling with three children was seen by another passenger assaulting one of the youngsters, a boy aged two or three.
The child was hit three times and kicked in the head and chest.
The man and the children got off the train at Alnmouth station.
The incident happened on Sunday, February 12, on the 4pm service, just before the train departed Edinburgh Waverley station for Peteborough.
Officers would like to speak to anyone who witnessed the alleged incident or anyone who could help identify those involved.
The man is described as white, of large build, with short dark hair. He was wearing glasses, dark jeans and white Nike trainers.
Investigating officer, PC Joss Froggatt, said: “I would like to speak to anyone who was on board this service who may have seen or heard the incident. It is unclear at this stage exactly what took place, but we have had serious allegations made, so we are investigating to establish what happened.”
Anyone with information can contact PC Froggatt on 0800 405040 or text 61016, quoting reference number 324 12/2/17.