British Transport Police are appealing for information after a child was assaulted on board a train travelling from Edinburgh Waverley to Peterborough.
The incident happened last Sunday on the 4pm service, just before the train departed Edinburgh Waverley station.
A man was travelling with three children and was seen by another passenger assaulting one of the children, a boy aged two or three years old.
The child was hit three times and kicked in the head and chest.
The man and the children alighted at Alnmouth station.
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, 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.
“If you have any information, please contact me by calling 0800 40 50 40 or text 61016, quoting reference number 324 12/2/17.”